Paris (CNN) -- French presidential frontrunner Francois Hollande vowed Friday to crack down on illegal immigration, as he and incumbent Nicolas Sarkozy battle to win over the public ahead of a second-round vote.
Hollande, of the center-left Socialist party, will hold a rally in the central city of Limoges Friday evening, while Sarkozy addresses supporters in Dijon, to the east.
The pair face a run-off vote for the presidency on May 6. Sarkozy received 27.2% of the vote in the first round of voting last Sunday, just behind Hollande's 28.6%.
Speaking to French radio station RTL Friday morning, Hollande said that the number of legal economic migrants should be limited and that he wants to "fight against" illegal immigration.
Immigration has been a key election issue, alongside the struggling economy and high unemployment figures.
Hollande's comments came hours after the two rivals were quizzed on television channel France 2 Thursday night, taking turns to answer journalists' questions.
Hollande, who was first to be put on the spot, said he feels "confident" and the political left's results had been even better than hoped for.
"Nothing is decided until the people have spoken. I have three duties: to put things right in France, to apply justice where it has been missing, and to bring together the French around a great cause -- the young people."
Sarkozy, who leads the center-right UMP party, defended his record, saying: "I have been president for five years. I've tried to protect France with all my might."
He said predictions of a landslide for the left in the first round had not been borne out, with the far-right National Front leader Marine Le Pen coming third, well ahead of far-left candidate Jean-Luc Melenchon.
Since Sunday, both Sarkozy and Hollande have sought to reach out to the 6.5 million people who voted for the National Front, giving it 18% of the vote.
"They are not from the extreme right, they are expressing themselves through a vote of crisis or of loyalty," Sarkozy said on France 2.
"I would like to say to them that I respect them. When someone suffers or protests, we must listen to them in order to be able to provide them with responses."
However, Sarkozy rejected any notion of striking a deal with the far-right group in remarks Wednesday.
The National Front's tough line on immigration appears to have struck a chord with many voters.
Responding to a question on Thursday's TV show, Hollande said, "There are too many foreigners" in France. "But that does not mean that we must expel those who are here on our territory."
Hollande, who has previously avoided that question, said those who are in France legally would be able to remain -- but those who do not have the right to live there would be driven out.
Sarkozy said he wanted to cut by half the number of foreigners allowed into the country over the next five years.
The reason, he said, is that he wants to welcome them in the right way, "with housing and employment, and that from now on, before all entries onto French national soil ... an exam on the French language and republican values should be passed."
Immigrants should have rights and responsibilities equal to those born in France, he said, even if he is opposed to extending them the right to vote.
Hollande also addressed France's position in Europe, saying Germany would have to negotiate on a fiscal pact agreed by the eurozone in order to permit growth.
"It's not Germany who will decide everything for all of Europe," he said. "We are not just any country in Europe. We are one of the leaders of Europe."
The two contenders will take part in their first head-to-head televised debate next Wednesday.
If elected, Hollande would be France's first left-wing president since Francois Mitterrand left office in 1995. Sarkozy has been president since 2007.
CNN's Saskya Vandoorne contributed to this report.