France's two presidential contenders continued to battle over the country's undecided voters Thursday, after sparring over the economy in their one head-to-head debate ahead of Sunday's runoff vote.

In a combative televised debate Wednesday night, President Nicolas Sarkozy and challenger Francois Hollande focused on the economy, social issues and immigration.

But despite the trading of personal insults, neither landed a killer blow, leaving both candidates keen to seize the advantage in the last two days of campaigning.

Centrist candidate Francois Bayrou announced Thursday that he would vote for Hollande, but urged his supporters to vote with their conscience.

Both candidates hope to pick up a share of the 9% of votes that went to Bayrou in the first round.

Sarkozy, of the center-right UMP party, was to hold a rally in the southeastern city of Toulon Thursday, while Hollande, of the center-left Socialist party, addressed supporters in the southwestern city of Toulouse.

The economy and immigration have been at the heart of campaigning, with France struggling to overcome with low growth and 10% unemployment.

In his opening salvo Wednesday night, Hollande said he would be the president of unity, justice and recovery.

"I want to unite all the French. ... It is in this way that we will recover our confidence," he said.

Sarkozy's response was to highlight the imminent danger in which he sees the country. "We are not in a crisis, but among many crises," he said.

In a direct appeal to the country's undecided voters, he then said: "Unity is when we talk to the people of France, not just to the left."

He also accused Hollande of favoring union members over the general public interest, and said with his opponent as president there would be "more taxes and more debt."

Hollande in turn attacked Sarkozy on divisions in the country, saying he has split the population.

In one of several testy exchanges, he also accused Sarkozy of cronyism.

"You appointed your close colleagues everywhere, in all the ministries and regional government. If I understand correctly, you appointed them everywhere," he said.

In response, Sarkozy, who is trailing in opinion polls, questioned his rival's grasp on the truth.

"Can I finish my sentence? What you are saying now is a lie. It is slander. You are nothing but a little slanderer," he said.

Accusations of dishonesty again came to the fore in another exchange.

"What is extraordinary about your answers is that whatever happens in France, you are happy, although the French are clearly not," Hollande said.

"What you are saying is a lie," Sarkozy responded. "When you say I don't care about my responsibilities, that is a lie."

Hollande, who in campaigning has sought to paint Sarkozy as more interested in looking after a wealthy elite than the common people, stressed his own commitment to social justice.

"I will be the president who believes in justice, because we are living through a difficult crisis, which is hitting those who work the hardest, who have less money," Hollande said. "I want justice to be the foundation of all the decisions that we make."

On immigration, Sarkozy repeated his position that France has too many immigrants to be able to provide the necessary jobs and housing.

"France is an open country; I know myself where I am from. But we have welcomed in too many people, we have to reduce the number of those that we allow in, not because we do not love them," he said.

He said France has always had very generous social benefits but immigration should be halved.