THE first wave of American and British strikes unleashed against Afghanistan in response to the US terror attacks had caused "very considerable damage", Foreign Secretary Jack Straw said today.

As military planners were assessing the effect of last night's air and missile attacks, Mr Straw said the action would continue until Osama bin Laden terrorist network in the country was destroyed.

"We are certainly not talking days unless something absolutely dramatic happens. We are talking weeks," he told BBC Radio 4's Today programme.

"It will be sustained until a judgment is made that the action has been successful."

Targets across Afghanistan were bombarded overnight by 50 Tomahawk Cruise missiles - some launched by the Royal Navy submarines HMS Trafalgar and HMS Triumph - and US warplanes.

The first wave of attacks were aimed at knocking out the Taliban regime's air defences in preparation for further operations over the coming days and weeks.

The targets included sites in the capital Kabul and the cities of Jalalabad and Kandahar, and military installations at Farah in the far west and Mazar-i-Sharif and Kondoz in the north.

The Taliban today summoned an emergency Cabinet meeting to discuss the attacks amid unconfirmed reports of civilian casualties - one report claimed 20 dead - coming from the region.

They insisted however that bin Laden and the Taliban's spiritual leader Mullah Mohammed Omar had both survived the onslaught.

Mr Straw insisted that the attacks had been carefully planned to keep civilian casualties to a minimum.

"We believe them to have been successful. We also believe them to have been proportionate and planned," he said.

In neighbouring Pakistan, where there were reports of demonstrations against the action, the President, General Pervez Musharraf, said that he hoped that the action would be short.

He sought to calm anger in his country - where many sympathise with their fellow Muslims.

"I also hope that this operation should not be perceived as a war against Afghanistan or the people of Afghanistan," he said.

"It's an action against terrorists, terrorism and their sanctuaries and their supporters."