An appeals court in Pakistan has thrown out the death sentences of two men who had been convicted of killing four Americans in the southern city of Karachi five years ago.

The four American oil workers were employees of Union Texas Petroleum. They were gunned down along with their Pakistani driver on their way to work in central Karachi in 1997.

Two years later an anti-terrorism court found two local political activists, Ahmed Saeed and Mohammed Saleem, guilty of committing the crime. They were both given death sentences in addition to seven-year jail terms.

A defense lawyer told reporters on Monday that a provincial high court in Karachi has thrown out the death sentences, citing a lack of evidence. However, he says the court has upheld the jail terms.

The defendants are said to be members of a regional political party, the MQM, which dominates Karachi politics. It is now a coalition partner in the national government.

Charges against the party's self-exiled leader, Altaf Hussain, and seven other activists have also been dropped. Pakistan's government can appeal the ruling to the Supreme court.