British Prime Minister Tony Blair (search) said he will undergo a medical procedure Friday to correct an irregular heartbeat, calling it a routine treatment that won't prevent him from seeking another term in office.

The 51-year-old prime minister said the procedure will involve local anesthetic and will not affect his job.

"It's a sort of fluttering. It doesn't stop you working, and indeed I've been working the last couple of months since it happened," he said Thursday night, just hours after appearing onstage for the closing ceremony of his Labour Party's (search) annual convention. "I'm going to go in and have this routine operation tomorrow."

Blair has had his toughest two years as prime minister, facing intense opposition — not least from within his own party — to his support for the U.S.-led war in Iraq.

The war overshadowed this week's convention, held in the southern seaside town of Brighton (search), and Blair is battling to unite his party as it aims to seek a third term in power.

Apparently aware that the health scare would prompt questions about his future, Blair sought to reassure the public by saying he intends to serve a full third term if his party is re-elected in national elections expected next year. He stressed he would not seek a fourth term.

His announcement Thursday followed months of speculation that he intended to step down midway through a third term in office and pass the baton to his powerful Treasury chief Gordon Brown.

Blair will be sedated during the 21/2-hour procedure, called a catheter ablation for the heart condition supraventricular tachycardia, which is caused by rapid electrical activity in the upper parts of the heart and results in a sometimes irregular, rapid heartbeat.

The procedure involves inserting a catheter through the groin and up to the heart, where radio-frequency energy is used to kill off the cells conducting the extra impulses.

Blair's office at No. 10 Downing St. said the prime minister will spend Friday night in the hospital and rest over the weekend before returning to "normal duties" on Monday. He will go ahead with a scheduled visit to Africa on Tuesday, the office said.

Blair said his doctor assured him that it wasn't connected to anything more serious.

"I feel fine. I feel great. What happens every so often is that you get a flutter. ... Apparently there is a procedure that is very easy to do and fixes it," he said.

The British Heart Foundation said the condition, which may be accompanied by shortness of breath, dizziness or fainting, can be distressing for the patient but is not considered serious.

Blair's condition first came to public attention a year ago when he was treated at a London hospital for a rapid, irregular heartbeat. An electric jolt was used to return his heart rhythm to normal.

On that occasion, he returned to work a day later, defying doctors' orders to take 24 hours of rest.

A month later, in November 2003, his aides were quick to play down another health scare when Blair called doctors to his official residence. The prime minister's office said he was suffering from a stomach ache that passed quickly with no treatment given by the two doctors who were examining him.

Blair's procedure will come less than a month after his 58-year-old former colleague in the White House, Bill Clinton, underwent quadruple bypass surgery in New York City.

Blair has seen his popularity slump since the Iraq war and the U.S.-led coalition's failure to find evidence supporting his prewar contention that Saddam Hussein possessed stockpiles of weapons of mass destruction.

During a speech to his party's conference Tuesday, Blair acknowledged British intelligence on the weapons threat posed by Iraq was wrong, but pointedly refused to apologize for toppling Saddam, insisting the world was safer with him in prison.

But the usually bullish and defiant prime minister was contrite. "I'm like any other human being, as fallible and as capable of being wrong," he said, insisting that he went to war to protect Britain's security.