US President George W. Bush ordered the strike less than four weeks after terrorists flew hijacked airplanes into the World Trade Center twin towers and the Pentagon.

A Pentagon official said the initial strike involved 50 Tomahawk cruise missiles, launched from ships. General Richard Myers said 15 bombers and 25 strike aircraft, both sea and land-based, were also involved in the military operation. The strike came at 12:30pm EDT; nighttime in Afghanistan.

About four hours later, a second round of more intensive air-attack was made against Taliban targets in Afghanistan.

Myers, sworn into office less than a week ago, termed the strike "the early stages of ongoing combat operations" against the Taliban regime in Afghanistan and bin Laden's al-Qaida network. He said the attacks included B-1, B-2 and B-52 bombers as well as ships and submarines that have been deployed in the region in the days since September 11.

The first strikes took place about 8:45pm Sunday as witnesses reported explosions in Afghanistan's capital Kabul and the southern city of Kandahar, the Taliban's spiritual home. The raids were expected to last well into the early morning hours in Afghanistan. Pentagon officials said the attacks would include strikes by U.S.-based B-2 bombers and B-52 and B-1 bombers flying from the British base at Diego Garcia in the Indian Ocean.

The Pentagon said it was targeting air defenses, terrorist training camps and other strategic military targets linked to the Taliban. The attacks began with cruise missile strikes launched from US and British ships in the Arabian Sea, including at least one British submarine. US fighter planes from aircraft carriers also were involved, Pentagon sources said.