U.S. President Barack Obama, flanked by Secretary of State Hillary Clinton and Defence Secretary Robert Gates, announces a new comprehensive strategy for Afghanistan and Pakistan on Friday in Washington. (Ron Edmonds/Associated Press)

Washington will send an extra 4,000 U.S. soldiers to Afghanistan to train that country's military and police forces, as well as substantially increase civilian aid efforts, U.S. President Barack Obama said Friday.

Flanked by his national security team, Obama laid out his revamped strategy for Afghanistan and Pakistan during a news conference in Washington.

"We will shift our emphasis to training … Afghan security forces so they can eventually take the lead in securing their country," he said.

Washington would like to see the country's army enrolment reach 134,000 by 2011. Currently, it stands at 83,000.

The extra American trainers, who will be paired with Afghan army units, will follow the summer arrival of 17,000 new soldiers already ordered to Afghanistan by Washington. Obama said the extra troops will help provide security ahead of Afghan presidential elections in August.

Obama called the situation in Afghanistan "increasingly perilous," with Taliban attacks against American troops and their NATO allies rising steadily.

"We have a clear and focused goal to disrupt, dismantle and defeat al-Qaeda in Pakistan and Afghanistan and to prevent their return to either country in the future," said Obama.

Afghan President Hamid Karzai said in a statement Friday that the strategy will benefit both the Afghan people and the region and increases the chance that his government and its international partners will successfully address the rising militant threat in the country.

Support for Pakistan

Security in Afghanistan is inextricably linked to Pakistan, said Obama, adding al-Qaeda leader Osama bin Laden and his top lieutenants are likely hiding out in Pakistan's lawless border region, which Obama called "the most dangerous place in the world."

"If Afghanistan's government falls to the Taliban, that country will again be a base for terrorists who want to kill as many of our people as they can," he said.

The president asked Congress to pass a bipartisan bill to give Pakistan $1.5 billion in economic support each year for the next five years to help build roads, schools and hospitals. In return, Pakistan's government must show it is working to combat militants in the border region with Afghanistan.

"Pakistan must demonstrate its commitment to rooting out al-Qaeda and the violent extremists within its borders. We will insist that action be taken one way or another when we have intelligence about high-level terrorist targets," said Obama.

U.S. Secretary of State Hillary Clinton and U.S. Defence Secretary Robert Gates will organize regular meetings between American, Afghan and Pakistani officials to discuss economic and military issues, said Obama.

Legal, agricultural experts needed

Obama's new strategy also includes adding hundreds of civilian advisers to those already in Afghanistan. The civilian surge would concentrate on improving life for ordinary Afghans, and would include experts in agriculture in a country where subsistence farming is the norm, as well as experts in education and law.

The civilians are also meant to help extend government services and the administration of justice.

"We are not in Afghanistan to control that country or to dictate its future. We are in Afghanistan to confront a common enemy that threatens the United States, our friends, and our allies and the people of Afghanistan and Pakistan who have suffered the most at the hands of violent extremists," said Obama.

The plan didn't include a timetable for troop withdrawal.

More than 2,800 Canadian soldiers are serving in Afghanistan. Since the mission started almost seven years ago, 116 soldiers have been killed. One diplomat and two aid workers have also been killed.

Defence Minister Peter MacKay said the U.S. is now moving in the same direction as Canada.

"The approach that they're advocating is very much the joined up whole of government approach, something we've been doing now for some time," said MacKay.

"As well, advocating for a regional approach that, of course, includes Pakistan, but I suggest in the bigger picture will include the input of countries like China, Russia, Iran."

Foreign Affairs Minister Lawrence Cannon said in a statement that the reviewed strategy "looks to be a very compelling, comprehensive and realistic assessment of the situation."

Liberal Leader Michael Ignatieff also welcomed the plan.

"I'm very pleased to see that [Obama] is putting in place a strategy that has a military component, a civilian component, but also a diplomatic component with respect to Pakistan," he said.

Canada's combat mission is set to end in 2011.

Obama's moves come ahead of a United Nations conference on Afghanistan next Tuesday in The Hague, where Clinton will join representatives from more than 80 countries. Obama himself is attending a NATO meeting next week in France and Germany.

At that meeting, the U.S. expects some NATO coalition members to commit more forces to the flagging war in Afghanistan, Obama officials said Thursday. They did not get specific.

Roughly 65,000 international forces are in Afghanistan, more than half from the U.S.

With files from the Associated Press