Two U.S. soldiers and their Afghan interpreter were in stable condition Wednesday, one day after being injured in the first-ever grenade attack on American forces in capital, a military spokeswoman said.

The two U.S. Special Forces soldiers were on a routine trip through the city Tuesday when an Afghan man tossed a grenade at their unmarked Russian jeep.

One of the soldiers suffered an eye injury and the second was wounded in the leg, U.S. military spokeswoman Capt. Alayne Cramer said at Bagram Air Base, north of the capital.

"They're in stable condition. They were not life-threatening injuries," Cramer said.

She said the Afghan interpreter was also in stable condition, but had no other details.

The U.S. military has declined to identify the wounded soldiers but said their families have been notified. She said the two were working in Kabul to help train the new Afghan national army.

Cramer said the three were treated at a hospital run by the international peacekeeping force, known as ISAF, and were still there early Wednesday.

She said one of the soldiers might be released later Wednesday and the other might be transferred to a U.S. medical facility at Bagram.

Cramer said the attack was the first of its kind on American troops in the capital and U.S. forces were taking it "seriously."

"We understand that it's threatening out there and we try to take appropriate measures," Cramer said. "Force protection is our number one priority ... we take this very seriously."

Afghan police arrested two men on Tuesday, including the man who allegedly hurled the grenade.

Interior Minister Taj Mohammed Wardak said the attack was linked to the al-Qaida terrorist network.

U.S. forces are frequently attacked with crude rockets at bases in eastern Afghanistan. On Nov. 28, a sniper shot a U.S. Special Forces soldier in the leg in the east, and escaped.

Fifteen U.S. servicemen have been killed in combat or hostile situations in Afghanistan since the U.S.-led anti-terror campaign began last autumn. The most recent fatality was on May 19.