U.S. officials say Vice President Dick Cheney made an unannounced visit to Afghanistan Monday to discuss concerns about the Taleban insurgency with President Hamid Karzai.
Cheney arrived from Pakistan, where he met with President Pervez Musharraf.
A Pakistani official said Cheney praised Pakistan's contribution to the war against terrorism during the meeting but urged General Musharraf to do more.
The official said Mr. Musharraf reiterated Pakistan's resolve and assured Cheney that Pakistan is doing its best.
The New York Times newspaper published an article Monday saying the U.S. Congress could cut aid to Pakistan unless Mr. Musharraf becomes more aggressive in hunting down terrorists.
The article said American intelligence officials believe the terrorist infrastructure is being rebuilt, and that while Pakistan has attacked some camps, its overall effort has fallen short.
It was unclear whether Cheney participated in talks Monday between President Musharraf and visiting British Foreign Secretary Margaret Beckett.
Cheney arrived in Islamabad from Oman.
U.S. officials have yet to comment on Cheney's visit to Oman, which has long been a military ally of Washington.
But, officials there said Cheney was to meet with Omani leaders to discuss the Iranian nuclear dispute, the situation in Iraq and the Israeli-Palestinian conflict.
Oman and other Gulf states have expressed concern about Iran's nuclear ambitions, but also say they hope for a peaceful resolution to Tehran's dispute with major powers.
Cheney has also visited Australia and Japan during his trip.
Some information for this report was provided by AFP, AP and Reuters.