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.

2004

October 9 - Presidential election. Karzai declared winner and sworn in on December 7.

2005

September 18 - Elections for a lower house of parliament and provincial councils. Parliament sits for first time on December 19.

2006

Jan 31 - Afghanistan receives pledges of $10.5 billion to help it fight poverty and the drug trade and improve security.

July 30 - NATO forces take control of security in the south, moving from Kabul and the safer north and west.

October 5 - NATO's International Security Assistance Force (ISAF) assumes responsibility for security in all of Afghanistan.

2007

March 2 - Pakistani security forces capture Mullah Obaidullah Akhund, the Taliban's third most senior leader, in Quetta.

May 13 - Mullah Dadullah, a Taliban commander in the south, killed in a clash with Western and Afghan forces in Helmand.

2008

June 12 - Donors pledge about $20 billion in aid at a Paris conference, but say Kabul must do far more to fight corruption.

July 7 - Suicide car bomb hits Indian embassy in Kabul, killing 41 people.

August 19 - Suspected Taliban insurgents kill 10 French troops and wound 21 in ambush east of the capital, the biggest single loss of foreign forces in combat in Afghanistan since 2001.

December 5 - Karzai and new Pakistani President Asif Ali Zardari pledge to boost cooperation and agree a joint strategy to fight al Qaeda and other militants along their shared border.

2009

January 27 - Thousands of U.S. troops move into two key provinces in east Afghanistan as part of strategy of outgoing U.S. President George W. Bush's administration.

February 17 - New U.S. President Barack Obama orders 17,000 more U.S. troops to tackle an intensifying insurgency.

March 27 - Obama announces plans to send a further 4,000 U.S. troops to train Afghan security forces, along with civilian personnel to improve delivery of basic services.

March 29 - Karzai announces he will stay in office after his term officially ends on May 21 until elections are held in August. He later says he'll run for re-election.

May 11 - Top U.S. and NATO commander in Afghanistan General David McKiernan is fired by Obama. His exit signals a shift from a conventional strategy to a counter-insurgency plan, aimed at lessening civilian deaths.

June 15 - U.S. General Stanley McChrystal assumes command of international troops in Afghanistan.

June 25 - Obama funding bill gives $79.9 bln to wind down the war in Iraq and ramp up operations in Afghanistan and $1.4 bln of aid for Pakistan, which is fighting a growing Taliban insurgency of its own.

July 2 - U.S. Marines launch assault in lower Helmand river valley in southern Afghanistan.

(Writing by David Cutler, London Editorial Reference Unit; Editing by Gill Murdoch and Paul Tait)