HERAT, Afghanistan (Reuters) - Afghan forces abandoned a remote district in the west of the country, leaving the area to Taliban insurgents after the government failed to resupply dozens of troops stationed there, provincial officials said on Wednesday.

Local officials said the Shebkoh district of Farah province, bordering Iran, has been under Taliban siege for months, making it difficult for the government to send reinforcements.

Mosa Nazari, deputy governor of Farah, said Afghanistan’s military leadership faced difficulty supplying and reinforcing the troops in Shebkoh district and it had been decided to withdraw in order to avoid casualties.

“The plan to leave the district was there for months and it was finally decided,” Nazari told Reuters, adding that the forces withdrew all ammunition and vehicles to the provincial capital of Farah.

U.S. military advisers have regularly pressed Afghan commanders to concentrate their forces and avoid exposed outposts that are difficult to defend and supply.

The Taliban, fighting to drive out foreign forces and re-impose its version of strict Islamic Law, said in a statement the Afghan government abandoned the district after a heavy firefight overnight, and the group seized an amount of ammunition.

A sparsely populated province, Farah has been the scene of intense fighting since the beginning of the year. Afghan forces have suffered heavy losses, including the killings of dozens of well-armed elite special forces there.

Shebkoh is a route for narcotics being smuggled from Helmand, the main source of poppy cultivation in Afghanistan, to Farah and Iran.

Afghan officials have accused Tehran, which the United States says is trying to extend its influence in western Afghanistan, of providing the insurgents with money, modern weapons and explosives. Iran denies the accusation.

Areas of western Afghanistan have seen heavy fighting in recent days. Last week, at least 14 Afghan soldiers were killed and 20 captured when Taliban fighters attacked an outpost in Shindand district in Herat, the province neighboring Farah.

Afghan and foreign forces have recently increased air strikes, targeting and killing senior Taliban commanders, including the powerful shadowy governor of Helmand province last week.

U.S. diplomatic efforts to begin peace talks with the Taliban have picked up with appointment by Washington of Zalmay Khalilzad, a former U.S. ambassador to Kabul, as a special peace envoy.