American aircraft pounded Taliban lines north of Kabul for the second time in two days, as Colin Powell, the Secretary of State, said he wanted to see the Afghan capital captured within the next few weeks before the onset of winter.
Jets bombed the area around Mazar-i-Sharif, the strategic city that the opposition Northern Alliance forces are trying to seize, and the front line north of Kabul.
It was the second major attack in two days day on these positions. Earlier, just before nightfall, there was the distant roar of jet engines overhead. Then US planes attacked the Taliban's forward positions, south of the disused military airfield at Bagram, sending plumes of smoke and dust into the air.
Speaking in Shanghai, where he was attending the Apec summit with President George Bush, General Powell said he expected the Northern Alliance to move more aggressively on Kabul. "It would be in our interest to see this matter resolved before winter strikes and makes our operations that much more difficult," he said.
General Powell, who indicated the opposition was closing in on Mazar-i-Sharif, said America would not necessarily suspend operations for the Islamic holy month of Ramadan, which starts in the middle of November.
Mr Bush has given the CIA sweeping powers to do "whatever is necessary" to kill Osama bin Laden and destroy his al-Qa'ida network. The agency is expected to direct covert operations of the kind launched at the weekend by American and British commando units in the Taliban stronghold of Kandahar.
Washington said similar missions were probably taking place again yesterday, testing the Taliban defences and checking hideaways of Mr bin Laden. The first raids were just a "warm up", General Wesley Clark, the former Nato supreme commander, said.
Downing Street indicated last night that the British commitment would go beyond the deployment of covert forces. The Prime Minister's spokes-man said the contribution to the action was unlikely to be only air support and the use of submarines in the Indian Ocean.
He refused to comment on whether the SAS had been involved in ground operations so far, but added: "It is recognised that we have world-renowned expertise in this area ... we are in detailed discussion with the US about other forms of contribution," he said.
He conceded there was a risk of casualties as the military action proceeded, but insisted there was widespread support for the Government's strategy.
In the opposition-held area north of Kabul, military commanders of the Northern Alliance gathered in Bagram's half-wrecked control tower and watched with intense interest as four waves of American aircraft launched attacks.
Ever since the air assault started 15 days ago, they have been asking for air support to soften up the Taliban lines north of Kabul. Down below, soldiers pointed excitedly skywards at the planes and cheered.
Until yesterday, America appeared to be holding back on making an attack here for fear of offending Pakistan, which is determined to prevent its long- time enemy, the Northern Alliance, capturing Kabul.
In response to the American raids the Taliban, which claims to have repulsed Friday's ground incursions and killed 20 to 25 US troops in the process, said it was distributing heavy weapons and mobilising villagers across the country to resist the new threat.
But these claims were dismissed as wishful thinking by General Richard Myers, chairman of the Joint Chiefs of Staff. He said US forces would take Mr bin Laden alive if possible, but if necessary "bullets will fly".
As the anti-terrorist campaign was stepped up in Afghanistan, fears of biological terrorism in America grew with confirmation that a Washington postal worker whose office sorts mail for the Capitol was "gravely ill" with the most dangerous inhaled form of anthrax.
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