The Taliban has stepped up its rhetoric against Washington and said it had given Osama bin Laden "free rein" to retaliate against US targets.
The Taliban's hardening of tone coincided with its decision yesterday to charge a French journalist, who had smuggled himself into the country dressed as a woman, with spying.
Diplomats in Islamabad said they feared for the life of Michel Peyrard, a correspondent for Paris Match.
Afghan experts were divided on whether any significance should be read into yesterday's remarks by the Taliban.
However, Gen Aslam Beg, the former head of the Pakistan army, said the warning should be taken "very seriously".
He said: "Previously the Taliban said that they had bin Laden under house arrest and I think they were sincere.
"Now they are saying that their resources are at Mr bin Laden's disposal so that he can communicate with his network of supporters around the world."
Mullah Abdul Salam Zaeef, Afghanistan's ambassador to Pakistan and his country's sole foreign envoy, echoed bin Laden's video-taped threat to the US by warning that American citizens could be under threat.
"As long as America is shedding the blood of Afghans it will not be beneficial to America," Mr Zaeef said.
"If America is continuing attacks on Afghanistan it will also not be safe."
Taliban officials claimed yesterday that "dozens" of civilians had died during two nights of US-led attacks in Afghanistan but by last night, only four deaths had been independently confirmed, those of Afghan aid workers who died when their United Nations-funded office was hit on Monday.
Mullah Zaeef said the attacks had destroyed houses, but Taliban fighters had been prepared and had suffered no casualties.
Otherwise, independent corroboration of civilian casualties, which is a matter of acute political significance in Pakistan and other Muslim nations where the strikes have sparked street protests, was virtually impossible.