DUBLIN - A crisis in Ireland's ruling party escalated Sunday after the foreign minister tendered his resignation and said he would not back Prime Minister Brian Cowen in a confidence vote this week.

Foreign Minister Micheal Martin, seen as Cowen's closest rival for the leadership of the ruling Fianna Fail party, said that he would be voting against the prime minister in the parliamentary party vote on Tuesday.

Cowen's popularity has slumped after Dublin was forced to turn to the EU and IMF for a bailout worth tens of millions of euros (dollars) in the wake of a savage recession.

"I welcome the decision of the Taoiseach [prime minister] to table a motion of confidence in himself at next Tuesday's parliamentary party meeting," Martin told reporters in Dublin.

"I will, in accordance with my views, be voting against the motion of confidence."

Martin said that he had tendered his resignation but Cowen "had indicated that he believes such a course of action is not necessary".

His announcement late Sunday came just several hours after Cowen challenged his party to back him or sack him in a secret confidence vote this week, amid growing pressure over his handling of the financial crisis.

The crisis in Fianna Fail, which rules Ireland in coalition with the Green party, came to a head in recent days after revelations emerged in a new book about Cowen's links to the former boss of Anglo Irish Bank before it was nationalised.

Ireland was hard hit by the financial crisis, and its banking and property sectors were hammered. Last month, the Irish parliament voted for a bailout worth 67 billion euros (90 billion dollars) by the EU and IMF.

After several days consulting with his party, Cowen announced on Sunday that he wanted to continue as leader of Fianna Fail as it was in the best interest of Ireland.

"I have come to the conclusion that I should continue to lead the party," he told a press conference in Dublin.

"I believe this to be in the best interest of the stability of the government, the country and our party."

He added: "For Fianna Fail, the party is important but the interests of the country are paramount."

On Tuesday's confidence vote, he said: "I believe that any issue regarding my leadership of Fianna Fail should be resolved immediately.

"By taking this initiative, I believe I am acting in the best interests of the party and its membership and I am confident of the outcome."

And he added once a vote had been taken, "we will unite behind whatever decision is taken".

Pressure increased dramatically on Cowen after it was revealed he had previously undisclosed contacts with Sean FitzPatrick, the bankrupt former boss of Anglo Irish.

FitzPatrick, who was questioned by police last year, resigned as chairman of the lender in December 2008 when it was revealed he moved some 87 million euros in personal loans in and out of the bank to conceal them from the public.

Anglo, which had been Ireland's third biggest bank, was nationalised two years ago after heavy exposure to the property market and has come to represent the reckless lending that characterised the country's bubble years.

Opinion polls show Cowen's personal popularity rating and those of the coalition have slumped to record lows since Ireland had to seek an international bailout.

A recent survey by Red C showed Cowen had just a 10 percent popularity rating and that only 14 percent of voters would give a first preference vote to Fianna Fail at the upcoming general election.