Australian foreign minister Kevin Rudd has announced his resignation in the latest sign of turmoil within his country's ruling Labor Party.

Rudd announced the decision during an official visit to Washington late Tuesday, saying he could not continue in office without the support and confidence of Prime Minister Julia Gillard.

Australian media have reported in recent days that allies of Rudd were plotting an internal party coup similar to the maneuver that unseated Rudd as prime minister and placed Ms. Gillard at the head of the party in 2010.

Gillard supporters have called for Rudd to be fired from the cabinet in response. Rudd complained Tuesday that Ms. Gillard has failed to repudiate those demands.

Following Rudd's ouster as prime minister, Ms. Gillard led the Labor Party into elections in which it barely squeaked back into power with the support of a handful of independent members of parliament.

Recent polls have shown the Labor Party trailing far behind the opposition Liberal Party, but show Labor would perform better with Rudd as its leader.

Ms. Gillard insists she has the support of her parliamentary caucus and has expressed confidence she would survive any attempt at an internal coup.