By Renee Maltezou
ATHENS (Reuters) - Greek Prime Minister Antonis Samaras on Thursday warned the country risked a "catastrophic" return to the depths of its debt crisis if his government fell, raising the stakes before a presidential vote this month.
Greek stock and bond losses accelerated after the comments by Samaras, who is stepping up rhetoric against his archrival -- the anti-bailout Syriza party -- in a bid to win the backing of lawmakers in the presidential vote and avoid early elections.
"We shed blood to take the word `Grexit' away from the mouth of foreigners, and Syriza is bringing this word back to their mouths," Samaras said in a speech to party lawmakers. "All lawmakers must now decide if we will elect a president or go to snap elections that people don't want, the markets are afraid of and which might have catastrophic consequences for the country."
Syriza responded by saying that Samaras's speech was a sign the government - who controls 155 lawmakers - knows he cannot muster the 180 votes needed to win the presidential vote.
"He does not even hesitate to beg markets to attack the country," Syriza said in a statement. "He is fooled if he thinks that by rekindling the same old issue of a euro exit he can terrorise people who have been asphyxiated by the bailout."
Failure to elect a president triggers early elections, which opinion polls show Syriza is likely to win. Samaras this week brought the presidential vote forward by two months -- leaving a final bailout review and plans for an exit from the programme up in the air while he seeks parliamentary backing.
It is a gamble that forces independent and small-party lawmakers to decide whether to back Samaras's politically tricky plan to pull the country out of the woods or the uncertainty of snap elections that would push the country deeper into crisis.
Investors have already been shaken by the sudden return to political upheaval in Greece. Greek shares fell 7 percent on Thursday, tumbling 21 percent so far this week.
The country's borrowing costs have also inverted sharply in recent days, with 10-year yields shooting back up over an unsustainable level of 9 percent.
The vote to elect a president will be held in three rounds starting Dec. 17 and end on Dec. 29. Snap national elections will be held in January if the government loses, Samaras said.
"We will all be judged in the coming days," Samaras said. "People do not want elections."
If the government prevails, Samaras promised Athens would quickly move to complete a pending bailout review, seek debt relief from European partners and sign a precautionary credit line to support the country in an interim post-bailout period.
Greece's funding needs were covered until the end of February, Samaras said, after Athens raised an additional 1.6 billion euros in a Treasury bill auction on Wednesday.
(Additional reporting by Lefteris Papadimas and Angeliki Koutantou, Writing by Deepa Babington; Editing by Angus MacSwan, Larry King)