A United States military delegation has arrived in Pakistan to discuss plans for Washington's campaign against Afghanistan's ruling Taliban and the suspected terrorist, Osama bin Laden.
Pakistan's president, General Pervez Musharraf, has promised full cooperation with the US as it hunts down those responsible for the attacks on Washington and New York.
"I can confirm that they are here," Mark Wentworth, spokesman for the US embassy in Islamabad, told Reuters.
In a televised address to the country last week, the Pakistani leader revealed that President George W Bush had asked for access to Pakistani airspace, the sharing of intelligence on Afghanistan and unspecified logistical support.
In return, Bush has already lifted economic sanctions imposed for its 1998 nuclear tests and he has agreed to reschedule some $600 million in debts to Washington.
Meanwhile the US defence secretary, Donald Rumsfeld has rejected claims by the Taliban that bin Laden has gone missing in Afghanistan.
"They know where he is," he said. "It is just not believable that the Taliban do not know where the network can be located and found and either turned over or expelled."
A spokesman for the Taliban leader, Mullah Mohammad Omar, said on Sunday that it was not clear whether the Saudi-born militant was still in Afghanistan.
Meanwhile international support for Bush's coalition to fight terrorism is growing.
The Central Asian Republic of Kazakhstan became the latest country to voice support for an international coalition on Sunday, when the President Nursultan Nazarbayev said he was ready to join in efforts to fight terrorism.
Nazarbayev spoke of his readiness in a televised meeting with Pope John Paul II, who is on a four-day official visit in the country.
But Kazakhstan was not alone in pledging support for the terrorist hunt. The Gulf Cooperation Council (GSC), made up of six Gulf Arab States, also gave assurances "of their support and cooperation with international efforts" to find the perpetrators of last week's terrorist attacks and "bring them to justice".
In a press communiqué, the GSC also urged the international community to make every effort to halt what it described as "terror acts" by the Israeli government against the Palestinians.
Bush lifts sanctions on India and Pakistan
Earlier on Sunday, Bush lifted sanctions against India and Pakistan as more ships and warplanes headed into position for a potential strike on Afghanistan.
The waiving of sanctions, imposed on the two countries in 1998 for their nuclear tests, had been widely expected after Pakistan agreed to cooperate with the United States in its hunt for bin Laden.
Bush said the continued sanctions "would not be in the national security interests of the United States".
US officials said Bush was also expected to issue an executive order designating specific groups and individuals as "terrorists", in a move designed to lock up their financial assets in the US.
European Union finance ministers meeting in Liege also agreed to speed up ratification of an existing United Nations resolution calling for the freezing of the Taliban's assets.
Afghanistan's Taliban government on Sunday reiterated that it would only hand over bin Laden if evidence of his involvement in the attacks was provided. The Saudi-born militant denies he had a hand in the plot.
"There is no change in our decision," said Abdul Hai Mutamaen, a Taliban spokesman. "American demands are not in favour of Muslims and Afghans and we are not ready to accept this."
However, the Taliban is finding itself increasingly isolated after the United Arab Emirates, one of only three countries to recognise the hardline government, severed all diplomatic ties with Afghanistan on Saturday.
Bush is due to meet Canadian Prime Minister Jean Chretien on Monday, and to receive the Japanese prime minister, Junichiro Koizumi, the next day in an effort to build an international coalition for the "war on terrorism."
swissinfo with agencies