Hundreds of angry protesters have booed French President Nicolas Sarkozy, forcing him to take shelter in a bar as he campaigned in the Basque country ahead of April's presidential election.
Some in the crowd then threw eggs at the bar guarded by riot police in the south-western town of Bayonne.
Mr Sarkozy described the protesters - Basque nationalists and supporters of his rival Socialist candidate Francois Hollande - as "hooligans".
He left the bar after about an hour.
The Basque region straddles south-western France and northern Spain.
Mr Sarkozy was met in Bayonne by a hostile crowd, who jeered him and shouted insults.
Some chanted "Nicolas kampora", which in the Basque language meant "Nicolas get out".
Mr Sarkozy was also showered with campaign leaflets calling for greater Basque autonomy.
Riot police had to be deployed around the Bar du Palais, where the president took refuge.
Visibly angry, Mr Sarkozy later denounced "the violence of a minority and their unacceptable behaviour".
"Here, we're in France, on the territory of the French republic, and the president of the republic will go everywhere. And if that doesn't please a minority of troublemakers, too bad for them", he said.
He also said he was "saddened to see Hollande's Socialist militants associating with [Basque] separatists in violent protests to terrorise ordinary people who want just one thing: to meet and talk with me".
A senior member of Mr Hollande's campaign team later said that while the party leader condemned any violence, no Socialist was involved in the Bayonne incident, the AFP news agency reports.
Opinion polls show that Mr Sarkozy is lagging behind Mr Hollande, although the current president is narrowing the gap.