Two more U. S. troops are killed in Afghanistan

Four U. S. servicemen have died in combat this year.

Two U. S. servicemen were killed Wednesday by a gunman dressed in an Afghan security forces uniform who fired on them at a base in southern Afghanistan. It was the latest in a recent string of U. S. deaths in the war- torn country.

Coalition soldiers returned fire, wounding the gunman and another person in an Afghan security forces uniform, according to a coalition statement.

Last weekend, three American contractors were killed in a car bomb attack in Kabul. This month, an Army Green Beret was killed on a NATO base in Kabul.

Despite the recent spate of attacks, U. S. and coalition casualties are down dramatically in Afghanistan compared with prior years. The fewer casualties reflect a decrease in the number of American troops in the country as Afghan security forces take the lead in battling insurgents.

Taliban forces have stepped up violence recently, causing Afghan troops to suffer record casualties and allowing the militants to take control of some districts around the country.

Some of the increase in attacks may reflect jockeying for power after the recent news of the death of Taliban leader Mullah Mohammed Omar, said Michael O’Hanlon, an analyst at Brookings Institution. “You’ve just got to expect fluctuations” in violence, O’Hanlon said. “We are going to see ups and downs.”

Wednesday’s attack raises to four the number of U. S. troop combat deaths in Afghanistan this year, according to Pentagon statistics. Since 2001, when U. S. forces invaded the country to oust the Taliban for harboring alQaeda leaders, more than 1,800 U. S. troops have died in combat.

It was not clear whether the assailant was a member of the Afghan security forces or posing as one. If he was an Afghan soldier, it would be the third so- called insider attack this year, the Associated Press reported. Three American civilian contractors were killed in January by an Afghan soldier. In April, an American soldier was killed by an Afghan soldier in Nangarhar province.

In 2012, there were 47 attacks by Afghan security forces on coalition troops that killed 62 people.

Since then, the number of insider attacks decreased as U. S. forces improved tactics and the number of American troops in the country declined.

JAWAD JALALI, EUROPEAN PRESSPHOTO AGENCY Window panes were left shattered after a blast in Kabul on Saturday. Several people, including American contractors, were killed in a suicide car bombing.

WAKIL KOHSAR, AFP/ GETTY IMAGES Afghan firefighters hose down a street in Kabul outside Camp Integrity, a base housing U. S. special operations forces that was attacked by militants Aug. 8.