A cell phone text message is straining relations between the two parties in Portugal's coalition government, which plan to stand together in a general election later this year.

Prime Minister Pedro Passos Coelho, in a new biography published late Tuesday, spills some secrets about the tough times his government has endured since imposing austerity measures following the country's 2011 bailout.

He claims Paulo Portas, head of the junior party in the center-right coalition, informed him by text message that he was quitting as foreign minister during a political crisis two years ago that almost brought down the government.

Portas's Popular Party responded to the embarrassing revelation in a statement, saying the resignation "was naturally formalized by letter." It added that the book's author had not consulted Portas about the claim.