Cambodia's prime minister has applied for a pardon for his political rival, a move that would allow the self-exiled opposition leader to come home and campaign for the upcoming general election.

Cabinet spokesman Phay Siphan says Prime Minister Hun Sen sent a letter Friday to King Norodom Sihamoni applying for the pardon for Sam Rainsy. The pro-government DAP news agency reported that the king has signed the request, though Phay Siphan could not confirm that.

The request came after the U.S. and others had said the exclusion of Sam Rainsy from July 28 elections called into question the polls' legitimacy. Hun Sen is expected to extend his 28-year rule.

Sam Rainsy has lived abroad since 2009 to avoid serving 11 years in prison on charges widely seen as politically motivated.