KABUL, June 13 (Reuters) - Hundreds of Pakistani families have fled from a surge of fighting between Pakistani government forces and militants into neighbouring Afghanistan, an Afghan government official said on Friday.
Pakistani government forces have been launching air strikes against Pakistani Taliban fighters in a northwestern valley near the Afghan border in recent days, after Taliban fighters raided the country's biggest airport, in Karachi, late on Sunday.
Missile-firing U.S. drone aircraft have also, for the first time in six months, attacked militants this week in Pakistan's North Waziristan region, a lawless militant stronghold on the Afghan order.
Millions of Afghan civilians have for decades sought shelter in Pakistan to escape war in their homeland but the fighting in Pakistan this week has sparked a rare flow of civilians the other way.
"Around 300 Pakistani families have escaped because they are worried about fighting between Pakistani forces and Pakistani Taliban," said Jabar Nahimi, governor of eastern Afghanistan's Khost province, over the border from northwest Pakistan.
"We have provided aid for 100 of these families and the rest will be helped soon ... We have also provided vaccinations as we are concerned about polio."
Both Afghanistan and Pakistan are facing threats from al Qaeda-linked Taliban factions but relations between the neighbours are more often marked by mutual suspicion, and even hostility, rather than cooperation on security.
Pakistan for years supported the Afghan Taliban, who are fighting to expel U.S.-led foreign forces from Afghanistan, while battling the Pakistani Taliban at home.
Some Pakistani Taliban fighters, who want to overthrow the Pakistani state, are based in mountain hideouts in eastern Afghanistan, from where they raid into Pakistan.
Pakistan is considering a full-scale offensive against Pakistani Taliban fighters in its northwest which would likely push more villagers across the largely unmarked border into Afghanistan.
More than 30 people were killed in the Pakistani Taliban raid on Karachi airport.
(Reporting by Mirwais Harooni; Writing by Jessica Donati; Editing by Robert Birsel)