U.S. lawmakers are expressing concern about the security situation in Afghanistan, and are pressing the Bush administration to seek an expansion of the international peacekeeping presence in that country.

Nearly a year and a half after U.S.-led military action against al-Qaida terrorist targets and the ruling Taleban in Afghanistan, Bush administration officials are offering a mixed record of success in restoring stability to that country.

David Johnson, coordinator for Afghan assistance at the State Department, told the Senate Foreign Relations Committee Wednesday that infrastructure projects are moving forward, the seeds of a market economy have been planted, independent media have begun to take root, and schools have reopened.

But Mr. Johnson said despite the positive developments, there remains an underlying fragility.

"Taleban and al-Qaida remnants remain in Afghanistan," he said. "They continue their attempts to disrupt the efforts of the Afghan government, and the international community using disinformation, intimidation, and violence."

The ranking Democrat on the committee, Senator Joe Biden of Delaware, was more blunt. "There is no stability in Afghanistan," he said.

Senator Biden, and committee chairman Richard Lugar, an Indiana Republican, renewed their appeal to the administration to press for an expansion of the U.N.-mandated peacekeeping force in Afghanistan. The 4,800-member International Security Assistance Force (ISAF) has been limited to Kabul.

I agree with those who suggest that ISAF must expand its area of operations beyond the capital," Sen. Lugar said. "The need to maintain security, distribute aid and establish the credibility of the interim government exists throughout the country, not just the capital."

It is an appeal echoed by Afghanistan's Ambassador to the United States, Ishaq Shahyar.

"The expansion of ISAF is good for all Afghan people," he said. "We have known only war for the last generation. It will also help finish the job of extinguishing all vestiges of the Taleban and al-Qaida in Afghanistan so democracy has a chance."

Assistant Secretary of Defense for International Security Affairs Peter Rodman said chances for expanding ISAF are slim because limitations on the force were a condition for some countries becoming involved in the mission.

"They wanted the mandate limited to Kabul," he said.

Senator Lugar warned that the United States would lose credibility if it failed to follow through on its commitment to restore stability to the country.

His committee will hold another hearing on Afghanistan at the end of the month, at which time Afghan President Hamid Karzai is expected to testify.