Islamabad, March 22 (IANS) The release of CIA security contractor Raymond Davis, who killed two men in Lahore and later paid "blood money" to their kin to avoid trial, has put the country's head down in shame, Pakistan Tehreek-e-Insaf chief Imran Khan has said.

The Pakistan Peoples Party (PPP) and the Pakistan Muslim League-Nawaz (PML-N) had a "tacit understanding" and it was through their joint strategy that Davis was finally released, Khan alleged.

"This act of the rulers has had the nation's head down with shame," Khan was quoted as saying by Geo News TV channel.

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.

A court in Lahore acquitted him after he reportedly paid "blood money" in terms of Islamic compensation law to the kin of the dead.

A senior PML-N leader had, however, said the party did not agree with the government's stand on the Davis issue.

Chaudhry Nisar Ali Khan, leader of the opposition in the National Assembly, told Prime Minister Yousuf Raza Gilani that his party did not agree to the method used to release Davis.

"Nowhere in my conversation with the prime minister did I express confidence in the court verdict on Davis," he told The News International daily.

Imran Khan also said the drone strikes by the CIA in the country's northwestern region bordering Afghanistan, which lead to the death of many innocent people, were happening at the government's own will.