15 February 2011 Last updated at 23:36 ET
US Senator John Kerry has said a US man arrested for killing two Pakistani men will be subjected to a criminal inquiry at home if Islamabad released him.
Senator Kerry also expressed regret over the killings which have soured relations between the two countries.
The US official arrived in Pakistan on Tuesday in a bid to resolve the row sparked by the arrest of Raymond Davis for last month's shooting in Lahore.
Mr Davis was taken into custody after confessing to the shootings.
Mr Davis has said he shot the two men in self-defence as they were trying to rob him.
The US government has announced that it would prove before a Pakistani court later this week that Mr Davis has diplomatic immunity.
"It is customary in an incident like this for our government to conduct a criminal investigation. That is our law. And I
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