Pakistan is looking to hire lobbying firms in Washington after a gap of nearly eight years, seeking to refurbish its image in the United States at a time of deteriorating relations between the allies, two government officials told Reuters on Tuesday.

Ties have been particularly strained following a US unmanned aircraft strike that killed top Afghan Taliban leader Mullah Akhtar Mansour in western Pakistan last month, which Islamabad protested was a violation of its sovereignty.

Relations have also been tense since a plan to buy eight F-16 fighter jets from the United States fell through this May after the U.S. Congress refused to approve the deal.The deal, valued at $699 million, came unstuck after Congress refused to authorise the use of US government funds to pay for the aircraft under the Foreign Military Financing (FMF) program.

"Pakistan used to have lobbyists in Washington ... Now we want to relaunch the effort," said a senior government official, who asked not to be identified, as he was not authorised to speak to the media on the record.

Islamabad dropped its official lobbying efforts during the 1999-2008 military rule of General Pervez Musharraf, the official said, adding that the government had now decided it needed help selling its image.