Afghanistan's Karzai blasts US, marring Hagel visit

Afghan President Hamid Karzai ratcheted up his criticism of the United States, marring a debut visit by the new US defense secretary, Chuck Hagel, and highlighting tensions that could undermine Washington's strategy to wind down the unpopular war.

A day after two Taliban bombings killed 17 people, Karzai accused the United States and the Taliban of colluding to convince Afghans that foreign forces were needed beyond 2014, when NATO is set to wrap up its combat mission and most troops withdraw.

"Those bombs that went off in Kabul and Khost were not a show of force to America. They were in service of America. It was in the service of the 2014 slogan to warn us if they (Americans) are not here then Taliban will come," Karzai said in a speech.

"In fact those bombs, set off yesterday in the name of the Taliban, were in the service of Americans to keep foreigners longer in Afghanistan."

It was one of several inflammatory comments by Karzai and his government on Sunday and follow weeks of efforts by the Afghan leader to curtail US military activity in Afghanistan, including a call to kick American special forces out of an important province. US commanders see special operations forces as key to the end-phase of the conflict.

Hours after Karzai's speech, Hagel said he spoke "clearly and directly" about the comments during his first meeting with the Afghan leader since becoming US defense secretary on Feb. 27.

Hagel appeared at pains to be respectful of Karzai and avoid sharp criticism, but he told reporters that any collusion between the U.S. and the Taliban "wouldn't make a lot of sense."

The US and NATO commander in Afghanistan, General Joseph Dunford, was more categorical.

"We have fought too hard over the past 12 years, we have shed too much blood over the past 12 years, we have done too much to help the Afghan security forces grow over the last 12 years to ever think that violence or instability would be to our advantage," Dunford told reporters travelling with Hagel.

Of Karzai's remarks, he added: "I'll let others judge whether that's particularly helpful or not at the political level."

Still, politics will be key over the next several months, as the United States and NATO allies work to carry out their strategy of pulling out their troops and decide how large a residual force to leave behind after 2014.

NATO defense chiefs meeting in Brussels last month discussed keeping a combined US and allied force of 8,000-12,000 in Afghanistan, focusing on training Afghan troops and countering the remnants of al Qaeda, the Pentagon has said.

Any deal for a follow-on force, which Washington says must include immunity for US troops, would need Karzai's blessing.