KABUL, Afghanistan (AP) _ The United Nations announced Thursday that its staff will travel with armed government escorts on roads in southern Afghanistan, hours after gunmen fired at a U.N. vehicle in the country's east and injured two Afghan workers.

The attack on the U.N. refugee agency vehicle took place on a road in Sitakandaw in Paktia province, said Gen. Khial Baz, a division commander in neighboring Khost province.

``Two people were in the car, one driver and one employee of the U.N. High Commissioner for Refugees,'' Baz said.

U.N. officials in Kabul could not immediately be reached for comment.

Baz said both Afghans were brought to a hospital in Khost, but the U.N. employee was seriously wounded and evacuated by a U.S. helicopter to Bagram Air Base, north of the capital.

The United Nations was already reviewing security after gunmen ambushed several Afghan mine-clearers this month in southern Zabul province, the third attack on mine-clearers in recent weeks, spokesman Manoel de Almeida e Silva told reporters.

Suspected Taliban fighters have launched several attacks in the last two months in southern Afghanistan, including the killing of an International Red Cross worker and an Italian tourist.

Almeida e Silva said the Kabul government has agreed to provide escorts for U.N. vehicles in the provinces of Nimruz, Helmand, Kandahar, Zabul, the southernmost part of Uruzgan and eastern Farah.

``United Nations agencies are informing the authorities of routes most commonly used in these provinces. Whenever feasible, aid agency personnel from different agencies will travel together,'' he said.

``These measures reflect our commitment to continue operations in all areas to the maximum extent possible.''

Almeida e Silva said U.N. road missions in other provinces in the country would not require armed escorts, but trips in volatile provinces farther east along the Pakistan border were being approved on a case-by-case basis.

U.N. staff nationwide can already only travel by road between 6 a.m. and 6 p.m.

Last week, operations of the U.N. Mine Action Center for Afghanistan were suspended in ``insecure areas'' on the road from Kabul to the southern city of Kandahar after its deminers were attacked.

Four U.S. soldiers have been killed recently in fighting with suspected Taliban fighters, whom Afghan authorities say are reorganizing in a bid to destabilize President Hamid Karzai's government, which took power after the radical Islamic militia were overthrown in a 2001 U.S.-led coalition war.