TIMELINE: Milestones in the intensifying war in Afghanistan

(Reuters) - U.S. Marines launched a helicopter assault early on Thursday in the lower Helmand river valley in southern Afghanistan, spokesman Capt. Bill Pelletier said.

About 8,500 U.S. Marines have been deployed in Afghanistan's southern Helmand province, the biggest single element of 17,000 extra troops being sent as part of Washington's new strategy to stabilize Afghanistan.

Here is a timeline of major Afghan developments since 2001.

2001

October 7 - U.S. and British planes begin bombing to root out al Qaeda leader Osama bin Laden and his Taliban protectors.

November 13 - Anti-Taliban Northern Alliance forces enter Kabul.

December 5 - Afghan groups sign deal in Bonn on interim government headed by ethnic Pashtun tribal leader Hamid Karzai.

2002

June 19 - Karzai sworn in as president for 18 months.