The US Defence Secretary Donald Rumsfeld has flown into the southern Afghani city of Kandahar for a surprise visit one day after his trip to Iraq.
Mr Rumsfeld is expected to travel to Kabul later today for talks with Afghan President Hamid Karzai on the future of US troops in Afghanistan and the sharp growth in Afghanistan's heroin production since the allied invasion.
Mr Rumsfeld is expected to visit Pakistan later today for talks with President General Pervez Musharraf and defence officials.
Mr Rumsfeld is also expected to meet with Prime Minister Shaukat Aziz. A US embassy official in Islamabad confirmed the visit but refused to give any other details.
Pakistan is a key ally of the US in its war on terror, and Mr Rumsfeld's visit comes after Washington recently announced plans to sell US-made F-16 fighter jets to Islamabad.
It also comes after the US closed its consulate in the southern city of Karachi yesterday due to a security threat. The consulate was expected to reopen today. The consulate was the scene of a car bomb attack in June 2002 that left 14 people dead, all Pakistanis.
Pakistani Islamic militant groups have been angered by Musharraf's support for the US in its war on terror. Musharraf has banned several militant groups since the September 11th, 2001, attacks in America.
Pakistani intelligence agents, police and other security forces have arrested more than 700 al-Qaeda suspects, including some aides to Osama bin Laden, who were handed over to US officials for further investigations.