Paramilitary troops and police had been deployed in sensitive areas and were patrolling in armoured vehicles amid fears of a possible backlash, provincial police chief Rana Maqbool said. ``The police have been put on alert to make sure nothing goes wrong after the conviction,'' Maqbool said.

Two men belonging to an influential ethnic political party, the Muttahida Qaumi Movement (MQM), were sentenced to death here on Saturday. Judge Hussain Bux Khoso found Ahmed Saeed and Mohammad Salim guilty and sentenced them to death by hanging.

Americans Ephraim Egbu, 42, Joel Enlow, 40, Larry Jennings, 49, and Tracy Riticie, 41, along with their Pakistani driver, were ambushed and gunned down in Karachi on November 12, 1997.

MQM has condemned the verdict as an attempt to tarnish the party's image in theeyes of the international community. The party has admitted the convicts were party activists but denied they were involved in the murders. A party leader and senator Nasreen Jalil said lie-detector tests on the accused by the US Federal Bureau of Investigation (FBI) had cleared the two men.

Maqbool said Pakistani premier Nawaz Sharif took personal interest in the ``important case.'' ``US President Bill Clinton always used to ask Nawaz Sharif about the outcome of the case. We had a responsibility and we have fulfiled it. We did not solve the case because of any reward. We are not greedy,'' he said. Police plan to remove street signs advertising Washington's two-million-dollar reward for evidence leading to the arrest of the suspects.

Lawyers said ten other suspects are still at large, including MQM's most senior leader, Altaf Hussain, who lives in London. The two convicts have seven days to appeal to the High Court in southern Sindh province.