KABUL, Afghanistan (AP) — Six Afghan policemen were found dead Saturday in their station house in southern Afghanistan, where international troops are ramping up operations to take control of Taliban strongholds, an official said.

In the north, three Afghan policemen were accidentally killed by friendly fire, NATO said.

The bodies of the six policemen, who were shot, were found in Greskh district of southern Helmand province, said Dawood Ahmadi, a provincial spokesman. It wasn’t immediately clear who shot them, but insurgents fighting back against NATO forces also are targeting anyone who supports the coalition or the Afghan government.

The coalition reported two U.S. service members died Saturday and another was killed Friday in insurgent attacks in the south. NATO did not disclose details of their deaths. A fourth member of the coalition, a British serviceman, was killed Saturday in Nad Ali district of Helmand, the British Ministry of Defense said.

Thirty-eight members of the international coalition, including 24 Americans, have been killed so far this month, according to a count by The Associated Press.

In neighboring Kandahar province, another police station was attacked Friday in Kandahar city, according to the governor’s office. Two insurgents were killed, but there were no police casualties.

In the north, the three Afghan policemen were killed Friday when Afghan security forces who were under fire from insurgents called for air support in Darzab district of Jowzjan province, NATO said.

It said two helicopters fired a missile and 30-millimeter rounds. An investigation found three members of the Afghan National Police were accidentally killed and several more wounded by the air-weapons team, it said.

NATO said it was sending a team to the area to determine what happened.

In July, a botched NATO airstrike killed six Afghan soldiers in Ghazni province in the east. The coalition said the Afghan army unit gave the wrong location to international forces. The helicopter crew received permission to launch the airstrike because headquarters believed the Afghan soldiers were in another area of the province at the time, the coalition said.

Also in the north, five civilians were killed and two others wounded when a bomb exploded Saturday, the coalition reported.

In the west, a woman and two children were accidentally killed Friday in fighting that erupted as Afghan and international forces pursued a Taliban militant known to smuggle foreign fighters and weapons from Iran, NATO said.

Six insurgents were killed as they got out of a vehicle and several other suspected militants were detained during the operation in the Pusht Rod district of Farah province, the coalition said.

An air-weapons team then fired on the vehicle, which subsequently exploded. The joint force, which later found the three civilians dead at the scene, believed the vehicle might have been loaded with homemade explosives, NATO said.

“We deeply regret what occurred on yesterday’s operation,” U.S. Army Col. Rafael Torres, a spokesman for NATO, said in expressing condolences to relatives. “We are taking a step-by-step approach in investigating what went wrong.”

The United Nations has reported the number of Afghan civilians killed or injured in the war soared 31 percent in the first six months of the year, with Taliban bombings and assassinations largely responsible for the sharp rise. According to the U.N., at least 1,271 Afghans were killed and 1,997 injured — mostly from bombings — in the first six months of the year.

Despite the rise in violence, the government has ordered foreign and Afghan security companies to cease operations within four months — a move the U.S. has warned could impede relief and reconstruction efforts.

On Saturday, the Interior Ministry spokesman said the government was also initiating a plan to remove security barriers that block roads and streets in Kabul. The spokesman, Zemeri Bashary, said barriers protecting government and international facilities would be moved closer to the compounds “to facilitate the use of roads.”

The move follows widespread public complaints that security barriers have compounded Kabul’s traffic congestion. Major attacks in Kabul are far less common than in Baghdad, where moves to relax intrusive security measures may have encouraged insurgents to step up suicide attacks in the Iraqi capital.