Deposed Thai Prime Minister Thaksin Shinawatra.

POSTED: 1:53 a.m. EDT, October 3, 2006

BANGKOK, Thailand (CNN) -- Thailand's ousted Prime Minister Thaksin Shinawatra announced his resignation from his ruling Thai Rak Thai party Tuesday, two weeks after military officers seized power from him in a bloodless coup d'etat.

According to Thaksin spokesman Jakrapob Penkair, the former prime minister's resignation came in a three-page hand-written letter that was faxed from his London home to Thai Rak Thai party headquarters in Bangkok.

Thaksin reportedly told party members to redirect their attention to other careers.

"That means Thai Rak Thai is effectively finished," a top party official observed.

"He does not say a word of 'I shall return' or something in that regard but says that he will resume his public duty only when the time comes."

Thaksin was forced from office on September 19 while he was in New York to speak to the U.N. General Assembly.

He remains in exile in London while an army-appointed anti-corruption panel investigates his assets in the wake of the coup.

The tanks and troops that toppled Thaksin's civilian government are now off the streets of the Thai capital following the announcement that former army commander Surayud Chulanont will serve as prime minister until elections promised for October 2007 (Full story).

Surayud was sworn in Sunday. He said he wanted to settle the Muslim insurgency in Thailand's south that has claimed hundreds of lives.

CNN's Narunart Prapanya contributed to this report