PESHAWAR, Pakistan - Afghanistan has been drawing a fresh influx of jihadi fighters from Turkey, Central Asia, Chechnya and the Middle East, one more sign that al-Qaeda is regrouping on what is fast becoming the most active front of the war on terror groups.

More foreigners are infiltrating Afghanistan because of a recruitment drive by al-Qaeda as well as a burgeoning insurgency that has made movement easier across the border from Pakistan, U.S. officials, extremists and experts say. For the last two months, Afghanistan has overtaken Iraq in deaths of U.S. and allied troops, and nine American soldiers were killed at a remote base in Kunar province Sunday in the deadliest attack in several years.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, warned during a visit to Kabul this month about an increase in foreign fighters crossing into Afghanistan from Pakistan, where a new government is trying to negotiate with militants.

Two U.S. officials, who spoke on condition of anonymity because of the sensitivity of the information, told the Associated Press that the United States was closely monitoring the flow of foreign fighters into both Afghanistan and Pakistan.

Jihadist Web sites from Chechnya to Turkey to the Arab world featured recruitment ads as early as 2007 calling on the "Lions of Islam" to fight in Afghanistan, said Brian Glyn Williams, associate professor of Islamic history at the University of Massachusetts. Williams has tracked the movement of jihadis for the U.S. military's Combating Terrorism Center at West Point.

Local Afghans in the border regions are increasingly concerned about the return of the

Araban

or

Ikhwanis,

as Arab fighters are known in the Pashtun language, Williams wrote in a CTC paper. He said there were rumors of hardened Arab fighters from Iraq training Afghan Pashtuns in the previously taboo tactic of suicide bombing.

Turkey also appears to have emerged as a source of recruits. Williams estimated as many as 100 Turks had made their way to Pakistan to join the fight in Afghanistan.

"The story of Turkish involvement in transnational jihadism is one of the best-kept stories of the war on terror," said Williams, who noted that al-Qaeda videos posted on YouTube mentioned Turks engaging in the insurgency. "The local Afghans whom I talked to claim that the Turks and other foreigners are more prone to suicidal assaults than the local Taliban."

Dozens of Turkish Islamic extremists have trained in al-Qaeda camps in Afghanistan and taken part in attacks there, said Emin Demirel, an antiterrorism expert in Turkey. He said images of attacks on mosques or Muslim villages provided propaganda for recruiting young Turkish Muslims.

"Nowadays, they are effectively using the Internet to communicate with fellow militants, and police have difficulty in keeping tabs on several of the jihadist sites," said Demirel, author of several books on Turkish Islamic militant groups. "Turkish courts sometimes locally block access to one particular site, but it is still accessed outside Turkey. Those Web sites eulogize fallen fighters as martyrs in order to recruit among radical Muslim youths."

A senior official in Turkey's Interior Ministry said it had no information to corroborate claims of an increase in the number of Turks fighting in Afghanistan. The official asked not to be identified because Turkish rules bar civil servants from making statements to the media.

Al-Qaeda's recruitment drive stems from a slow and steady resurgence that started in 2002, according to Taliban sources.

"They are awake," said Qari Mohammed Yusuf, who Afghan authorities confirm is a senior Taliban. "They have people going by different names to other countries. They are coming and going easily. In the last year, they have been organizing more day by day."

Al-Qaeda has financed the Taliban in both Pakistan and Afghanistan, Yusuf told the Associated Press. In the chaos created by the Taliban groups, al-Qaeda has been able to steadily recruit, reestablish its public-relations wing, plot new attacks, and reestablish areas of operation on both sides of the border.

Some new recruits cross into Afghanistan's northern Balkh province or through Iran into Herat province in western Afghanistan, said Nangyal Khosti, a commander loyal to Jalaluddin Haqqani, a wanted extremist. The recruits, Yusuf said, head to Afghanistan's Paktika province, where there are roughly 150 Arab extremists.

In Pakistan, al-Qaeda recruits are sent to Waziristan and the lawless regions of the northwest along Afghanistan's eastern border, Yusuf said.

Afghan and Western officials say a key route for al-Qaeda recruits is from Central Asia into northeastern Kunar and Nuristan provinces, where former U.S. intelligence officials suspect Osama bin Laden is hiding. Both provinces border Pakistan's Bajaur tribal area, where the Taliban hold sway.