KABUL (AP) – Insurgents staged two attacks against police in Afghanistan on Thursday, killing nine officers and wounding six others, officials said, in the latest violence against the lightly armed force that has born the brunt of rising attacks across the country.

Washington has pushed to significantly increase the number of Afghan police and improve their training as a key part of a revised U.S. strategy for Afghanistan and Pakistan that President Barack Obama is expected to unveil fully on Friday. It is aimed at countering Taliban militants, who have made a comeback following their initial defeat by U.S.-led forces in 2001.

Obama has already pledged to send 17,000 additional troops to Afghanistan to battle the Taliban and could send even more as part of the administration’s new strategy.

Many of the troops will be sent to the south, the heartland of the Taliban insurgency, where militants attacked a police checkpoint Thursday, killing nine policemen in Helmand province’s Nahri Sarraj district , the Interior Ministry said. It blamed “enemies of Afghanistan,” a common reference to Taliban militants. Taliban militants also attacked a police convoy in central Ghazni province Thursday, wounding six policemen, regional police spokesman Iqbal Gul Sapan said. Four militants were killed in the clash in Nani village near the provincial capital, he said.

The Interior Ministry said the police were transporting a militant prisoner at the time, adding that two civilians were wounded in the attack.

Police often have fewer weapons and less training than Afghan and international troops, leaving them vulnerable to such attacks.

Richard Holbrooke, the American envoy to Pakistan and Afghanistan, said Saturday that the new U.S. strategy for Afghanistan would focus on improved recruitment and training of the national police force, aiming for a “very significant increase” in police numbers that would free up NATO and U.S. troops to concentrate solely on military actions to help stabilize the country. Better training also would be aimed at rooting out widespread police corruption, which has turned many Afghan citizens against the force.

Corruption also has been a significant issue at the highest levels of government, with reports that relatives of President Hamid Karzai have profited from their family connections, charges they denied.

Karzai said Thursday that the international community’s allegations of corruption against his government were false and politically motivated. He outlined his own savings and assets to head off any corruption allegations that might be leveled against him in the run-up to presidential elections later this year.

Karzai said he has about $10,000 in a bank in Frankfurt, Germany, and his wife has jewelry worth about the same amount. He said his salary is only about $500 per month. “I have no private car, no land, no garden, no house,” Karzai told a news conference.

After the Taliban’s defeat in 2001, many militants fled south and east into Pakistan. With the help of bases inside Pakistan, the Taliban have staged a violent comeback in the last several years that has threatened the weak central government.

U.S. and Afghan intelligence officials have said they suspect rogue elements in Pakistan’s intelligence agency of providing key information to the Taliban.

The New York Times carried a report on its Web site late Wednesday saying the assistance could go even further. The newspaper, citing American, Pakistani and other security officials who spoke anonymously because they were discussing confidential intelligence information, said the widening Taliban campaign in southern Afghanistan is made possible in part by direct support from operatives in Pakistan’s military intelligence agency, the Directorate for Inter-Services Intelligence.

The Times said the support consisted of money, military supplies and strategic planning guidance to Taliban commanders, with proof of the ties coming from electronic surveillance and trusted informants.

The Pakistani officials said they had firsthand knowledge of the connections, though they denied that the ties were strengthening the insurgency. The newspaper said the Pakistani Embassy in Washington declined to comment.