KABUL - The Afghan government will take part in a U.S. strategic review of the war in Afghanistan, President Hamid Karzai said Sunday in a sign of increased co-operation at a time of strained relations.

Karzai recently sent President Barack Obama a letter with a proposal that Afghanistan join a war review currently underway.

The U.S. special envoy to Afghanistan and Pakistan, Richard Holbrooke, said at a joint news conference that Obama had "welcomed the suggestion."

Karzai said his foreign minister, Dadfar Rangin Spanta, would head the delegation. The U.S. has several reviews of the situation in Afghanistan underway, and it was not immediately clear which one Afghan officials would take part in.

Holbrooke later told Afghanistan's Tolo TV that Pakistan is also sending a strategic review team to Washington alongside Karzai's team.

The U.S. is studying the situation in Afghanistan at a time of spiralling violence. Taliban attacks have spiked the last three years, and militants have swept up wide areas of countryside that the Afghan government has not been able to control.

Obama has said the U.S. will increase its focus on Afghanistan and draw down forces in Iraq under his watch. The U.S. is contemplating sending up to 30,000 more troops to bolster the 33,000 already in Afghanistan.

Karzai told the news conference he was "grateful" for an agreement announced Thursday between Afghanistan and the U.S. military that Afghan forces would take on a greater role in the planning and execution of missions with the aim of reducing civilian casualties.

He said he hoped the agreement would "reduce civilian casualties and prevent nighttime raids." Overnight raids by elite U.S. Special Operations Forces cause many of the civilian deaths that Karzai has repeatedly denounced, but the agreement made no mention that such targeted missions would end.

In recent weeks, Karzai has publicly pressed the United States to use Afghan troops on nighttime raids to prevent civilian casualties, criticism that has added to recent tensions in the U.S.-Afghan relationship.

The Afghan president said in a television interview Friday that he has not yet spoken with Obama over the phone since the U.S. president's inauguration, a clear sign that Karzai no longer enjoys the favoured status he held with former president George W. Bush.

Karzai told al-Jazeera that tension exists between Afghanistan and the U.S. over civilian casualties, arrests of Afghans and night raids.