BAYONNE, France — French President Nicolas Sarkozy took refuge from a crowd of several hundred angry protesters in a cafe, as riot police swarmed in to protect him while he campaigned in the country's southwest Basque country.

Riot police surrounded the Bar du Palais in central Bayonne where Sarkozy stayed for about an hour Thursday to get away from the protesters -- some of them Basque nationalists, others carrying posters of rival Socialist candidate Francois Hollande.

Even for the unpopular leader, it was a bizarre turn of events. The French president's security is scaled down when he is on the campaign trail, and some observers have noted it has been particularly spare at some recent events, perhaps as part of Sarkozy's effort to connect with voters.

But the quick reaction of riot police underscored how serious -- and strange -- the siege of a world leader was. Inside the cafe, where he met with residents of Bayonne, Sarkozy denounced "the violence of a minority and their unacceptable behaviour."

While he was inside, some of the protesters outside threw eggs toward the barrier of riot police guarding the cafe.

French TV repeatedly showed footage of the crowds throughout the afternoon, though the images were often of supporters.

The conservative Sarkozy trails Hollande, the front-runner, in the two pronged April and May presidential election.

"Here, we're in France, on the territory of the French republic, and the president of the republic will go everywhere," Sarkozy said once inside the cafe. "And if that doesn't please a minority of troublemakers, too bad for them."

In a campaign speech Thursday evening, Hollande exhorted his supporters not to become "advocates of vindictiveness" but "actors of hope." He did not make direct reference to the incident in Bayonne, but urged his followers to never resort to physical or verbal abuse.

Earlier, the narrow streets of the historic centre of Bayonne, in the French Basque country, were packed with supporters and protesters following Sarkozy during his visit. Tension mounted as Basque separatists threw pieces of paper at him. They were joined by others holding portraits of Hollande and his presidential program.

"If this is the concept of democracy, that the Socialists associate with Basque separatists, if this is it, the country they have in mind, it doesn't make you want to get there," Sarkozy said to reporters inside the cafe.

Sarkozy left the cafe escorted by riot police and protected by an umbrella.

The president's campaign spokeswoman, Nathalie Kosciusko-Morizet, asked Socialists to "respect the rules of democratic debate."

"It's not because you don't have ideas that you have to stop others from expressing theirs," she said.

Sarkozy declared his candidacy on Feb. 15. The latest polls show him narrowing the gap in the first round but lagging far behind in the final round. With the president now actively on the campaign trail, the debate has grown increasingly bitter with harsh denunciations by supporters on both sides.