KABUL (Reuters) - Two Afghan women working for a security firm searching people entering Bagram air base near the Afghan capital Kabul were killed on Wednesday and two others wounded by unknown gunmen, officials said.

The four were shot outside the base by two masked gunmen on a motorbike, said Wahida Shahkar, a spokeswoman for the provincial governor of Parwan.

“Two of them were killed and two wounded,” she said. “The attackers managed to escape the area.”

There was no immediate claim of responsibility. Taliban spokesman Zabihullah Mujahid said he was checking the report.

In June, six Afghan guards working at Bagram for a private security contractor were killed while on their way to work in an attack claimed by the Taliban.

There was no immediate comment from the U.S. military which runs Bagram, the largest U.S. base in Afghanistan.

The number of Afghan personnel working at Bagram was cut sharply last year after a mechanic detonated a suicide vest, killing four Americans and wounding 17 other people.