TEHRAN—Iran's elite military unit, the Islamic Revolutionary Guard Corps, has transferred lethal new munitions to its allies in Iraq and Afghanistan in recent months, according to senior U.S. officials, in a bid to accelerate the U.S. withdrawals from these countries.
The Revolutionary Guard has smuggled rocket-assisted exploding projectiles to its militia allies in Iraq, weapons that have already resulted in the deaths of American troops, defense officials said. They said Iranians have also given long-range rockets to the Taliban in Afghanistan, increasing the insurgents' ability to hit U.S. and other coalition positions from a safer distance.
Such arms shipments would escalate the shadow competition for influence playing out between Tehran and Washington across the Middle East and North Africa, fueled by U.S. preparations to draw down forces from two wars and the political rebellions that are sweeping the region.
The U.S. is wrestling with the aftermath of uprisings against longtime Arab allies from Tunisia to Bahrain, and trying to leave behind stable, friendly governments in Afghanistan and Iraq. Iran appears to be trying to gain political ground amid the turmoil and to make the U.S. withdrawals as quick and painful as possible.
"I think we are likely to see these Iranian-backed groups continue to maintain high attack levels" as the exit date nears, Maj. Gen. James Buchanan, the U.S. military's top spokesman in Iraq, said in an interview. "But they are not going to deter us from doing everything we can to help the Iraqi security forces."
In June, 15 U.S. servicemen died in Iraq, the highest monthly casualty figure there in more than two years. The U.S. has attributed all the attacks to Shiite militias it says are are trained by the Revolutionary Guards, rather than al Qaeda or other Sunni groups that were the most lethal forces inside Iraq a few years ago.
In Afghanistan, the Pentagon has in recent months traced to Iran the Taliban's acquisition of rockets that give its fighters roughly double the range to attack North Atlantic Treaty Organization and U.S. targets. U.S. officials said the rockets' markings, and the location of their discovery, give them a "high degree" of confidence that they came from the Revolutionary Guard's overseas unit, the Qods Force.
U.S. defense officials are also increasingly concerned that Iran's stepped-up military activities in the Persian Gulf could inadvertently trigger a clash. A number of near misses involving Iranian and allied ships and planes in those waters in recent months have caused Navy officials to call for improved communication in the Gulf.
Iran's assertive foreign policy comes amid a growing power struggle between President Mahmoud Ahmadinejad and Supreme Leader Ayatollah Ali Khamenei. Many of the president's closest aides have been detained on alleged corruption charges in recent weeks, raising questions as to whether Mr. Ahmadinejad will serve out his term.U.S. and European officials also say Iran has grown increasingly aggressive in trying to influence the political rebellions across the Middle East and North Africa. Tehran is alleged to have dispatched military advisers to Syria to help President Bashar al-Assad put down a popular uprising.
In recent months, according to U.S. officials, Iran has also increased its intelligence and propaganda activities in Egypt, Bahrain and Yemen, countries where pro-U.S. leaders have either fallen or come under intense pressure.
Iranian officials denied in interviews and briefings this week that the Revolutionary Guard played any role in arming militants in Iraq and Afghanistan. They charged the U.S. with concocting these stories to justify maintaining an American military presence in the region.
"This is the propaganda of the Americans. They are worried because they have to leave Iraq very soon, according to the plan," said Iranian Foreign Ministry spokesman Ramin Mehmanparast.
"They are better off going home and sorting out their own domestic problems."
Iranians officials have also accused the U.S. and Israel of interfering in Iranian affairs, including assassinating Iranian nuclear scientists and supporting opposition groups. The U.S. and Israel have denied this.
In recent weeks, Iran's leadership invited the presidents of Afghanistan, Pakistan and Iraq to Tehran to discuss regional affairs. Senior Iranian officials made it clear during those meetings that they wanted an accelerated exit of American forces from the region.
"Americans want to have permanent bases in Afghanistan, and this is dangerous because the real security will not be established as long as the American military forces are present," Ayatollah Khamenei told Afghan President Hamid Karzai last week, according to Iranian state media.
Iraq has in recent years been a proxy battlefield for the U.S. and Iran. U.S. officials in Iraq said the Qods Force is training and arming three primary militias that have in recent months attacked U.S. and Iraqi forces. Kata'ib Hezbollah, or Brigades of the Party of God, is viewed as the one most directly taking orders from Revolutionary Guard commanders in Iran. Two others, the Promise Day Brigade and Asa'ib Ahl al-Haq, are offshoots of the Mahdi Army headed by the anti-American cleric Muqtada al-Sadr, who currently lives in Iran.
Over the past six months, Kata'ib Hezbollah has escalated attacks on U.S. forces employing weapons called IRAMs, or improvised rocket-assisted munitions. The weapons are often propane tanks packed with hundreds of pounds of explosives and powered by rockets. Militiamen launch the weapons from the backs of flatbed trucks.
Kata'ib Hezbollah claimed credit for a June 6 IRAM attack that killed six American troops at Camp Victory, near Baghdad International Airport. This week, three more Americans were killed when an IRAM struck a desert base just a few miles from the Iranian border in Iraq's Wasit Province, according to U.S. officials.
"We believe the militias see themselves as in competition with each other," said Gen. Buchanan.
"They want to claim credit for making us leave Iraq."
The U.S. believes Iranian involvement in Afghanistan is significantly lower than in Iraq. But U.S. officials said they have seen clear evidence that the Revolutionary Guard has transferred longer-range rockets to elements of the Taliban that significantly enhance their ability to target U.S. and other NATO forces.
In February, British forces intercepted a shipment of four dozen 122-millimeter rockets moving through Afghanistan's desolate Nimruz Province near the Iranian and Pakistan borders. The rockets have an estimated range of about 13 miles, more than double the distance of the majority of the Taliban's other rockets.
"It was the first time we've seen that weapon," said a senior U.S. defense official in Afghanistan. "We saw that as upping the ante a bit from the kind of support we've seen in the past."
U.S. officials stressed that most of Iran's influence in Afghanistan is channeled through "soft power"—business, aid and diplomacy. But these officials said the deployment of more U.S. and NATO forces along the Afghan-Iranian border as part of the Obama administration's Afghanistan "surge" appears to have raised Iran's sense of insecurity.
These officials said Iran's support for the Taliban appears to wax and wane in relation to how successful Washington and NATO appear to be in stabilizing Afghanistan. Shiite-majority Iran has traditionally viewed the Taliban, a Sunni group, with trepidation. The two sides nearly fought a war in 1998 after the Taliban executed Iranian diplomats based in the central Afghan city of Mazar-i-Sharif.
"They're supporting the Taliban because they want us out of here," said the U.S. official in Afghanistan. "If we're making gains, I can see them upping their support. If they're making gains, they'll probably stay quiet."
In large part because of the growing wariness over Iran's backing of Shiite militias in Iraq, the U.S. is considering altering its withdrawal plans from the country, say administration and defense officials.
All U.S. forces are due to depart at the end of the year, but senior American officials have hinted loudly that they would like Baghdad to ask the U.S. to keep a viable force in the country beyond that date. Some administration and military officials have talked about retaining 10,000 troops in Iraq.
Military officials and defense analysts cite Iran as a prime justification for extending the U.S. presence. They say Iran is trying to use its military, which is much more powerful than Iraq's, and Shiite proxy militias inside Iraq to pressure Baghdad to maintain close ties with Tehran.
Adm. William McRaven, the administration's nominee to lead Special Operations Command, told a Senate panel this week that he favors keeping a commando force in Iraq that would be available to counter threats.