Afghan soldiers botched a brazen attempt to assassinate the defense minister at the capital's airport Saturday, while fighting in southern Afghanistan (search) left 30 suspected militants dead, officials said.

The violence came as U.S. military commanders warned in an interview with The Associated Press that Taliban (search) insurgents might try to disrupt the Sept. 18 legislative elections with "spectacular" assaults using car bombs and suicide attackers.

But Maj. Gen. Jason Kamiya (search), the top operational commander in Afghanistan, said he was confident that enough American troops and other forces were in place to ensure the balloting succeeds.

"We are in a posture to disrupt, pre-empt and discourage enemy actions," he said.

Asked if the election would be successful, Kamiya said, "I am 100 percent confident."

Meanwhile, a helicopter carrying Afghanistan's army chief and three Cabinet ministers crashed and burst into flames while taking off, but all on board escaped with only minor injuries. The government called it an accident.

Nine Afghan soldiers were arrested in the attempt to shoot Defense Minister Rahim Wardak at the airport, said ministry spokesman Gen. Mohammed Saher Azimi.

Four bullets hit his convoy as the vehicles left the airport, but Wardak and several other ministers had gotten out, he said. One bullet hit "the exact place where the defense minister had been sitting in the car," and a ministry staffer was wounded, Azimi said.

"It is clear that it was an assassination attempt on the defense minister," he said.

The motive for the shooting was not announced. A senior government official, speaking on condition of anonymity because he was not authorized to speak on the matter, said the soldiers were angry over a pay dispute.

Coming after last fall's presidential ballot, the Sept. 18 election is the next key step toward democracy after a quarter-century of war. Insurgents loyal to the ousted Taliban regime have stepped up activities the past six months seeking to wreck the vote, and more than 1,200 people have died in the fighting.

A U.S. military intelligence official, Chief Warrant Officer Larry Tersone, told AP that insurgents were expected to "start ramping up operations" even more. He said the main threat was believed to be car bombs and suicide attacks at polling stations.

"I think they will try to conduct an operation of a spectacular nature within a significant population center because that is the immediate attention-getter they are looking for," Tersone said.

He said the military also was on the lookout for lone militants using rockets against people lining up to vote.

About 20,000 American soldiers are in Afghanistan as part of a 21,000-strong U.S.-led coalition. There is a separate force of 11,000 NATO (search)-commanded peacekeepers.

Coalition forces have gone on the offensive in recent weeks, reporting the killings or arrests of hundreds of suspected insurgents during operations in volatile southern and eastern regions.

Azimi said Afghan and U.S.-led forces killed 30 suspected militants and arrested a large number of others Friday in southern Helmand province, which has suffered several insurgent attacks in recent weeks. Dozens of weapons were found in the area, including some lying in farm fields, he said.

The helicopter carrying army chief Bismillah Khan and three Cabinet ministers crashed during takeoff in the Panjshir Valley, about 60 miles north of Kabul. Presidential spokesman Khaleeq Ahmed blamed the crash on the chopper's rotor blades clipping a tree during takeoff.

The craft was about 30 yards in the air when it wobbled, then quickly descended, flipped on its side and crashed, said an AP photographer at the scene. It burst into flames and then exploded.

Azimi said Khan, Sediqa Balkhi, minister for the disabled, and the helicopter's two pilots, suffered minor injuries.

Hundreds of spectators, including government leaders and foreign ambassadors, fled as screaming as chunks of metal flew into a group of vehicles parked nearby.

The officials had attended a memorial service in honor of Ahmed Shah Masood (search), the former head of the U.S.-backed Northern Alliance who was killed by two suspected Al Qaeda (search) assassins Sept. 9, 2001.