Washington ? The Saudi government challenged the Bush administration Tuesday to prove its claims that Saudi citizens have traveled to Iraq to fight American troops, and said U.S. forces have failed to secure their side of the border.

“We are very concerned about this issue because we would like to take action,” Saudi foreign policy adviser Adel al-Jubeir said in an interview with The Associated Press. “But we have no evidence of Saudis crossing into Iraq and we have received no evidence from the U.S. government.”

Al-Jubeir said his government has offered to send its own team of investigators to help U.S. officials identify any possible Saudi expatriate who may have come through other countries, such as Iran, or who made it through the porous, desert borders between Iraq and the Saudi kingdom.

“We are willing to send a team to Iraq to look at any evidence they might have,” he said. “Saudi Arabia is determined to fight terrorism and to prosecute terrorists regardless of where they are.”

Al-Jubeir was reacting to comments by Bush administration officials over the last few days suggesting some foreign fighters have crossed from Saudi Arabia and other countries to help fight the American occupation in Iraq through sabotage, and attacks on soldiers.

Deputy Secretary of State Richard Armitage suggested Saudi Arabia was among three countries that had not stopped these fighters from crossing into Iraq.

Adel al-Jubeir, foreign policy adviser to the Saudi Arabian crown prince, has called on the United States to prove that foreign Islamic fighters are entering Iraq through Saudi Arabia.

“The ways these people are getting into the country is from Iran and from Syria and from Saudi Arabia,” Armitage said in an interview with the Arabic-language al-Jazeera television channel. “I’m not in a position to assert that the governments of Iran or Syria and Saudi Arabia are in any way responsible. But as a minimum I can state that … these fighters are not being stopped at the borders.”

Those comments came even as the Saudi government struck a deal to allow FBI and U.S. intelligence agents to create a new joint U.S.-Saudi task force to track terrorist financing in the kingdom

Al-Jubeir said Saudi guards were on full patrol along the Iraqi border, but that American troops have failed to occupy the border positions that were abandoned by Iraqi soldiers at the start of the war.

“We have raised this issue with the U.S. on a number of times, both before the war and after the hostilities ended,” al-Jubeir said. “We have raised the importance of sealing the Iraqi border with the U.S. government because of concerns there might be smuggling of weapons from Iraq into Saudi Arabia.”

The State Department said Tuesday that Saudi Arabia was cooperating in the war on terrorism but that more could be done.