US officials see early indications of Syria taking steps to restrict the ability of foreign fighters to cross its border into Iraq, where they have aided the insurgency for years, the top US commander in Iraq said Friday. "There is some possibility that Syria may have taken some actions to make it tougher for these foreign fighters to move through," Gen. David Petraeus said in an Associated Press interview at the Defense Department. He stressed that it is too early to say for certain that Syria is now heeding long-standing US calls to impede the movement of foreign fighters, whom US officials say are involved in some of the more spectacular attacks in Iraq. "They may be doing more than they certainly have in the past, which is not much, because they were not doing much in the past," Petraeus added. He said it was unclear what may be motivating Syria to be more helpful. "Syria has to worry in the long run that their soil does not become used by al-Qaida," he said. "They have to worry at what al-Qaida could do to them and their country. What al-Qaida wants, if you believe al-Qaida, is something very different from what the Syrian population certainly wants." Petraeus and other US officials also have complained about Iranian influence in Iraq, including Iranian supplies of arms to insurgent groups. In the interview, Petraeus, who took over as the top US commander in Iraq in February, said he was encouraged by progress in recent months against al-Qaida elements in Anbar province, the vast province that stretches west from Baghdad to the borders with Syria, Jordan and Saudi Arabia. Violence in Anbar has declined and US-backed Iraqi forces have gained a measure of control in keys cities including Ramadi, the provincial capital. Petraeus attributed the change in part to tribal leaders getting fed up with al-Qaida attacks on civilians and in part to the terrorist group's use of hijackings and other tactics that have disrupted tribal smuggling operations. "Al-Qaida was killing business," Petraeus said, adding that he believes the progress in Anbar will prove lasting.