Al Qaeda militants are coming from Iraq to fight in the insurgency in Afghanistan, a provincial governor said Thursday after interrogating an Iraqi caught sneaking into the country illegally.

Meanwhile, police said a homicide bomber disguised as a woman blew himself up at an army checkpoint in eastern Afghanistan on Wednesday, killing five Afghans, including three soldiers.

"There is a big group coming from Iraq," Nimroz provincial Gov. Ghulam Dusthaqir Azad said. "They're linked to Al Qaeda and fought against U.S. forces in Iraq. They have been ordered to come here. Many are suicide attackers."

It was not immediately possible to confirm the governor's comments with officials in Kabul. A spokesman for the U.S. military, Lt. Mike Cody, said, "We don't discuss detainees or intelligence matters."

Azad made the comments in a satellite telephone interview to The Associated Press from his office in the remote desert city of Zaranj after he questioned the Iraqi, who was identified as 35-year-old Numan din Majid from Diyala province, west of Baghdad.

Majid was arrested Monday in Zaranj, on the Afghan-Iran border, along with three Pakistanis, two of whom were believed to be militants from Kashmir, Azad said. They were all believed to have crossed into Afghanistan from Iran.

Also, five Bangladeshis were arrested in the city Tuesday and were believed to have links to the Taliban, Majid said.

The Interior Ministry confirmed the arrests Wednesday, but gave no details.

An upsurge in suicide attacks in recent months, previously rare in Afghanistan, has fueled suspicion that militants here could be copying tactics of insurgents in Iraq, but U.S. officials have said they don't have evidence of direct links between the rebellions.

Wednesday's blast occurred in eastern Khost province as Afghan soldiers were checking the assailant's vehicle, said Mohammed Ayub, the regional police chief. The attacker, sitting in the back seat, detonated explosives hidden under a woman's burqa shroud when soldiers asked to see his ID, he said.

Three Afghan soldiers, the driver of the vehicle and a farmer working nearby were killed, Ayub said. Three soldiers were wounded, as well as a second farmer.

Ayub accused the Taliban of being responsible for the attack.

"The bomber probably wanted to go into Khost city for a suicide attack there, but panicked and blew himself up when the soldiers started checking," he said.

Majid, the Iraqi who was arrested, was carrying in his pockets an Iraqi ID card and a photograph of former Iraqi president Saddam Hussein, Azad said. He was dressed in traditional garb and was carrying a single small bag of clothes.

"He confessed he took part in the war in Iraq against the Americans," the governor said.

He said the capture came two months after another Arab of unspecified nationality was caught sneaking across the border from Iran. He said that during questioning, the man claimed he was part of a group of 17 militants traveling individually from Iraq to Afghanistan.

"We handed him over to the anti-terrorism department and they have made several arrests based on information from him," Azad said.

There have been a series of protests across Afghanistan in recent weeks against the suicide bombings. On Thursday, more than 1,000 people demonstrated in southern Helmand province, demanding an end to the attacks, regional administrator Ghulam Muhiddin said.

He said students, Muslim clerics and other civilians took part in the rally and demanded the international community urge Pakistan to stop its alleged support of the militants.

Afghan officials have repeatedly claimed that the Taliban and other militant groups have training bases in Pakistan and are receiving support from that side of the border — an accusation Islamabad denies.