Islamabad, Sep 17 (IANS): Police Wednesday registered murder cases against Pakistani Prime Minister Nawaz Sharif and several of his ministers in the killing of opposition activists during the anti-government protests here, police and lawyers said.

A local court had ordered the police Monday to register the cases against the prime minister and 11 top officials, including the interior, defence and railways ministers and the city's chief commissioner and police chief, Xinhua reported.

The Pakistan Awami Tehrik (PAT) of religious leader Tahirul Qadri had approached the court to register cases in the killing two of its workers in police action on Aug 31 and Sep 1.

Clashes had erupted between the demonstrators and the riot police when the protesters tried to march to the Prime Minister's House. At least two protesters were killed and some 500 people, including dozens of policemen, were injured in the clashes.

No one has so far been arrested and legal experts said that registration of cases did not mean the people named were guilty.

Lawyers said the police now formally approached the Islamabad administration to initiate an inquiry into the case.

The PAT, in its application, had requested the court to register murder cases against Prime Minister Nawaz Sharif, two federal ministers, the Islamabad police chief and several more personalities.

A local court in Islamabad, in a short order, this week instructed the police to take necessary action on the application in line with the law.

Police in Islamabad said they would challenge the lower court's verdict after a detailed judgement was issued in the case.

Earlier, the Islamabad police in a report had told the court that the people mentioned in the application had nothing to do with the police action and that there had been no evidence about their involvement in the incident.

A defence lawyer of the government said the police did not have arms and they had only used rubber bullets to deal with the emergency situation.

A lawyer for the petitioner said that the police had "opened direct firing on the demonstrators and also used expired tear gas". He questioned the police action when the government had deployed army troops for the protection of important buildings.

It is the second time a judge has ordered registration of murder cases against the prime minister and several other ministers.

Last month, a court had ordered registration of murder case against the prime minister and 20 more people over the killing of a dozen PAT activists in the eastern city of Lahore in June.