DUSHANBE (Reuters) - Iran denied on Thursday accusations of involvement in Tajikistan’s civil war in the 1990s, labeling the claims an attempt to damage bilateral ties.

In a documentary aired by state television on Wednesday, three Tajiks said that, following training in Iran, they had killed politicians and other prominent figures inside Tajikistan during the 1992-97 war and attacked a Russian military base there.

The Iranian embassy in Tajikistan said the accusations were unfounded.

“The airing of such biased films... shows that certain circles do not want to see... stronger friendship between the two countries,” it said in a statement.

Tehran acted as one of the mediators in talks to end the war, which pitted government forces against an Islamist-led armed opposition.

But ties between the two nations, both Persian-speaking and predominantly Muslim, have been strained since a leader of a banned Tajik Islamist party attended a conference in Tehran in December 2015, which angered the government in Dushanbe.

President Imomali Rakhmon’s government banned the Islamic Renaissance Party of Tajikistan (IRPT) and jailed some of its leaders and activists, after accusing it of being behind a coup attempt in 2015.

IRPT leader Muhiddin Kabiri attended the Tehran conference after fleeing Tajikistan and being put on a wanted list by Dushanbe.