Britain said today a looming harsh winter and the holy month of Ramadan meant the race was on for the United States to achieve its immediate objectives in Afghanistan.
Officials also said talks were under way with the United States about possible future use of British troops.
The United States took its military campaign to a new level at the weekend, sending more than 100 special forces troops into Afghanistan on a mission which included the search of a command complex used by Taliban leader Mullah Mohammad Omar.
British Prime Minister Mr Tony Blair spelled out the near-term aims of the US and Britain as bringing Osama bin Laden and leaders of his al Qaeda network to justice, to stop them posing a continuing threat and to ensure that Afghanistan ceases to harbour and sustain terrorism.
Asked whether the two powers were striving to achieve their war aims before winter falls and Ramadan, the Muslim holy month, starts in about four weeks, British Armed Forces Minister Mr Adam Ingram said: "Clearly we are planning to try and achieve that very objective."
Britain also moved today to put an end to the anthrax scares that have disrupted life by announcing tough new laws for hoaxers.
Offenders could face up to seven years behind bars.