MOSCOW (AP) _ Tajikistan's government and opposition fighters agreed Saturday to exchange prisoners captured during a gun battle last week that left about 20 people dead, a news agency reported Saturday.

However, the two sides did not agree on how to organize the exchange, and U.N. observers were trying to mediate, the ITAR-Tass news agency reported from the Tajik capital, Dushanbe.

Opposition fighters have been holding more than 100 government soldiers since Tuesday, when the clash broke out in the town of Kofarnikhon, 20 miles east of Dushanbe. ITAR-Tass did not say how many prisoners the government may be holding.

The fighting, which lasted two days, was one of the most serious outbreaks of violence since the government and the mostly Muslim opposition in this former Soviet republic in Central Asia signed a peace deal last year ending a five-year civil war.

The United Nations, which brokered the peace accord, has blamed opposition fighters for sparking the violence.