Islamabad, March 17 (IANS) A petition was filed in a Pakistan court Thursday challenging the release of CIA security contractor Raymond Davis, who was let off Wednesday after paying compensation to the kin of the two people he had shot in January, a media report said.

The petition filed by barrister Iqbal Jafri in the Lahore High Court stated that the families of the two dead Pakistani nationals - Faizan and Faheem - were pressurised by the government into pardoning Davis, Dawn News reported.

The petition said Davis's pardoning and immediate release was in violation of the law, and requested the court to invalidate the decision and direct the authorities to initiate proceedings against those who brought about his release.

A court in Lahore Wednesday acquitted Davis after payment of compensation. A US Air Force plane carrying 12 men, reportedly including Davis, later took off from Lahore airport for Afghanistan.

Davis, 36, shot dead two Pakistanis on a motorcycle in Lahore Jan 27, in what he described as an attempted armed robbery. He claimed he acted in self-defence.

He was a member of a security team assigned to protect CIA operatives in Lahore collecting intelligence on militant groups.

Various religious and political parties as well as social and lawyers' organisations Thursday held protests in different cities against Davis's acquittal, Geo News said.

In Multan, lawyers of the district and high courts boycotted court proceedings, while activists of the Jamat-e-Islami staged demonstrations.

Political parties and the Labour Qaumi Movement held protests in Faisalabad.

Protesters chanted slogans against Davis and burnt tyres in Laki Marwat, Dera Ghazi Khan, Muzaffarghar, Charsada, and cities in Pakistan-administered Kashmir.