U.S. soldiers and Iraqi police arrested 14 Iraqis, including a militant suspected of leading a terrorist cell made up of followers of the extremist Wahhabi (search) sect of Sunni Islam (search), the military said Thursday.

Sami Ahmed (search), a former Iraqi intelligence service officer under Saddam Hussein, was captured late Wednesday, said Maj. Josslyn Aberle of the Tikrit-based 4th Infantry Division.

She said Ahmed, along with 13 other Iraqis, were arrested near Baqouba, 35 miles northeast of Baghdad, in a hotbed of anti-coalition activity within the Sunni Triangle. Wahhabism is the strict, fundamentalist branch of Sunni Islam from which Al Qaeda leader Usama bin Laden draws spiritual direction.

Five Iraqi police also were wounded in separate attacks on Thursday in northern Iraq. And a U.S. Army spokesman said a rocket struck the green zone in Baghdad where the headquarters of U.S.-led occupation authority is located after five large explosions rumbled through the center of the capital late Wednesday. No injuries or damage were reported.

In Ramadi, 70 miles west of the capital, Baghdad, nearly 1,000 people rallied to condemn the near simultaneous attacks against Shiite shrines Tuesday and called for national unity.

Sunni clerics, city officials, including the governor and members of the political parties, condemned the blasts.

The attacks -- at some of the holiest shrines of Shiite Islam and on the most sacred day in the Shiite calendar -- threatened to turn Shiites against Sunnis if the bombers were found to have been Iraqi Sunni extremists.

But strife with the country's Sunni minority would hardly be in the interests of the Shiites, who stand on the verge of achieving their dream of real political power after generations of suppression. Civil war would threaten those dreams, and the community's influential clergy appeared eager to keep passions in check.

On Wednesday, Shiite clerics joined Sunni preachers in a march of thousands of mostly black-clad men in Baghdad.

No group claimed responsibility for the attacks. However, the top U.S. commander in the Middle East, Gen. John Abizaid, said Wednesday that the United States has evidence that Al Qaeda-linked Jordanian militant Abu Musab al-Zarqawi was behind the bombings.

Abizaid's statement in Washington was the most direct assertion yet by a U.S. official that al-Zarqawi is carrying through on a terrorist campaign inside Iraq, as described in a letter purportedly written by al-Zarqawi and intercepted recently by U.S. intelligence.

An insurgent group in Fallujah, however, circulated a statement signed by the "Leadership of the Allahu Akbar Mujahedeen," that called the letter a forgery and claimed that al-Zarqawi was killed in the Sulaimaniyah mountains of northern Iraq "during the American bombing there."

There was no way to verify the authenticity of the statement, one of many leaflets put out by a variety of groups taking part in the anti-U.S. resistance. Coalition officials had no immediate comment.

The statement did not say when al-Zarqawi was supposedly killed, but U.S. jets bombed strongholds of the extremist Ansar al-Islam in the north last April as Saddam Hussein's regime was collapsing.

It said al-Zarqawi was unable to escape the bombing because of his artificial leg.

"The truth is, Al Qaeda is not present in Iraq," the Mujahedeen statement said. Though many Arabs entered the country to fight U.S. troops, only a small number remain, the group said.

In what appeared to be a nod to criticism from Shiite leaders, U.S. administrator L. Paul Bremer said the coalition would help strengthen border security, saying it was "increasingly apparent" that "a large part of terrorism" comes from outside Iraq.

"There are 8,000 border police on duty today and more are on the way," Bremer said Wednesday. "We are adding hundreds of vehicles and doubling border police staffing in selected areas. The United States has committed $60 million to support border security."

Shiites are believed to comprise about 60 percent of Iraq's 25 million people, and the collapse of Saddam's Sunni-dominated regime has offered them the opportunity to transform their numbers into domination of the government being worked out with the U.S.-led coalition.