The aerial surveillance will lead to a more dangerous phase of the military campaign, in which ground forces will pursue bin Laden.
As US fighters struck targets in Kandahar and Kabul yesterday, the Pentagon said it had virtually knocked out the Taleban's air defences, allowing more American and British troops to be sent to countries bordering Afghanistan.
"In the next week, you'll see people start moving," said one official.
A spokesman for the opposition forces in Afghanistan predicted yesterday that the Taleban would fall "in a matter of weeks ... if not days".
Abdullah Abdullah claimed that about 1200 Taleban soldiers, including 40 commanders, had defected, leaving Kabul with only one, indirect, supply route.
But the Taleban rhetoric was as fiery as ever. Its ambassador to Pakistan, Abdul Salam Zaeef, said the regime would "offer two million more martyrs for independence and sovereignty if need be".
The Taleban said they had lifted all "restrictions" placed on bin Laden after the September 11 strikes, and he was free to wage a holy war against the US.
"Jihad is an obligation on all Muslims of the world," said spokesman Abdul Hai Mutmaen.
Despite the defiance, many Afghans in Kabul were unwilling to spend another night of fear, and fled.
The US apologised for killing four Afghans who worked for a UN-sponsored mine-clearing operation.
UN Secretary-General Kofi Annan called the deaths "a hard blow".
Bombs also landed in a civilian area near a military hospital in a night raid on Tuesday morning (New Zealand time).
The number of casualties was not known.
In other developments:
* The Taleban arrested French journalist Michel Peyrard, disguised in a full-length burqa veil near Jalalabad, and said he would be tried as a spy.
* British Prime Minister Tony Blair headed for Oman after talks in Geneva with United Arab Emirates President Sheikh Zaid bin Sultan al-Nahayan. It is Mr Blair's second diplomatic mission in a week to shore up Arab support.
* Taleban soldiers exchanged gunfire with Pakistani border patrols in a pre-dawn clash in a remote tribal district, injuring four guards.