Updated

The U.S. ambassador to Iraq told The Associated Press on Friday that suicide bombings by two mentally retarded women in Baghdad strapped with remote-controlled explosives show that a resilient Al Qaeda has "found a different, deadly way" to try to destabilize Iraq. At least 73 people were killed, officials said.

"There is nothing they won't do if they think it will work in creating carnage and the political fallout that comes from that," Ambassador Ryan Crocker said in an interview at the State Department. "They have found a different, deadly way to do this. "Al Qaeda has been damaged, but ... it is still there, it is resilient and it is determined."

"Their car bomb capabilities have been badly disrupted so now, as we saw today and as we've seen for some time, they are moving toward suicide vests, in this case suicide vests worn by women," he said. "No one's doing victory dances, and today's horrific bombings illustrate why that's the case."

Crocker spoke after the remote-controlled explosives strapped to the two women detonated in a coordinated attack on pet bazaars in Baghdad, killing at least 73 people in the deadliest day since the U.S. sent 30,000 extra troops to the capital this spring.

"We and the Iraqis are going to have to stay on this until this threat is eliminated," he said. "It's going to be hard, it's going to be uneven and there are going to be days like today."

Crocker also said that Iran continues to play a negative role in training and supplying insurgents with weapons and explosives, but made clear he remains open to renewing a three-way security dialogue with Iranian and Iraqi officials.

A new meeting between the three sides could happen in "the next week or so," he said. But he noted that he had expected such talks to take place in early January after the United States indicated it was willing to participate a month earlier.

"The Iranians may be ready to come back to the table and if they are, we'll be there," Crocker said. "I am perfectly ready to sit down with my counterpart and would expect to do so."

However, he said a lower-level meeting of security officials would likely proceed any ambassadorial meeting, which would be his fourth with the Iranian ambassador to Iraq since he arrived in Baghdad nearly one year ago.

Another Iraqi neighbor, Syria, which Washington accuses of allowing foreign fighters to enter Iraq from its territory, appears to have clamped down on such border crossings, Crocker said.

"We have seen a downturn in the number of suicide bombers coming across" the border and that "was not just a coincidence," he said.

Security issues along with Arab support, including appointing ambassadors to Iraq, will be main agenda items at a meeting of foreign ministers of Iraq's neighbors to be held in Kuwait in early April, Crocker said.

He lamented that despite promises no Arab nation has yet to establish a permanent diplomatic presence in Iraq and urged regional leaders Egypt and Saudi Arabia to send ambassadors to Baghdad.

"I'm getting a little lonely out there," Crocker said.

The ambassador is in Washington for consultations on an agreement to be negotiated with Iraq on the status of U.S. forces in the country after the current U.N. mandate expires in December. He said he expected negotiations to begin this month.

He said he did not expect the agreement would specify how many U.S. troops will stay in Iraq and would not speculate on whether the force drawdown would continue after the summer. One Army brigade and two Marine battalions have already returned home and will not be replaced. Four other Army brigades are to come out by July, leaving 15 brigades, or roughly 130,000 to 135,000 troops in Iraq.

"Our redeployments have to be conditions-based," Crocker said.

He said the U.S. presence in Iraq would remain central to the country's security in the foreseeable future.

"We're the center of gravity," he said.