KABUL (Reuters) - Afghanistan officials said on Monday a Tajik or Russian aircraft had bombed a northeastern Afghan border district during a clash between gunmen and Tajik border guards, but officials in both Tajikistan and Russia denied that they had done so.

Cross-border clashes are rare on Afghanistan’s border with Tajikistan, compared, for example, with fighting along Afghanistan’s eastern border with Pakistan.

The air attack followed a clash between gunmen and Tajik border guards in Durqad district of Takhar province, two Afghan officials said.

Khalil Asir, a spokesman for Takhar provincial police, said eight Taliban were killed and six wounded in the air strike after a clash in which two Tajik border guards were killed.

“It was not clear if it was a Russian or Tajik aircraft,” he said.

Jawed Hejri, spokesman for Takhar provincial governor, also said it was not clear where the aircraft came from but he said the six people killed in the clash with Tajik border forces were drug smugglers.

An Afghan defense ministry spokesman declined to make any immediate comment.

A spokesman for Tajik border guards in Dushanbe said Tajikistan had not carried out any bombing and did not confirm the death of two border guards.

However, the official, who declined to be identified, said three Tajik forestry workers had been attacked by intruders from Afghanistan. Two were killed while the third escaped.

The official declined to give any more details.

Russia said its military aircraft had not conducted any operations near Afghanistan’s border with Tajikistan, the RIA news agency cited the defense ministry as saying.

Much of the porous Afghan-Tajik border is in mountains and difficult for Tajik authorities to police.

Afghan government officials say Russian forces, including aircraft, help Tajikistan with security against the Taliban and other militant groups. At the same time, drugs from Afghanistan are smuggled to the outside world through Tajikistan.

Taliban spokesman Zabihullah Mujahid said there had been a clash, and an air attack, but it was between drug smugglers and Tajik border guards and the aircraft bombed a forested area used by smugglers.

“Taliban fighters have no permission to clash with neighbor countries,” he said.

Lieutenant-Colonel Martin O’Donnell, a spokesman for U.S. forces in Afghanistan, said U.S. forces did not conduct any strikes in the area.

A retired Afghan air force general, Atiqullah Amarkhel, said those responsible for the air attack should be identified.

“Afghanistan has no control over its air space due to a lack of facilities. U.S. forces should follow up the case,” he said.