Mr Sarkozy (r) spoke at the funeral of police officer Jean-Serge Nerin
France's president has said the country will rid itself of bases run by the Basque separatist group Eta.
President Nicolas Sarkozy was speaking alongside the Spanish prime minister at the funeral of a French policeman whose death was blamed on the group.
The policeman was killed last week in an exchange of fire near Paris.
"We will eradicate all the bases of Eta one by one," Mr Sarkozy said. "We won't let France become the support base of terrorists and assassins."
He said that police would be "completely mobilised" for the task, adding that the killing of the policeman, 52-year-old father-of-four Jean-Serge Nerin, would "not go unpunished".
One person was arrested during the shootout at a car depot in Dammarie-les-Lys, which began after police apprehended a group suspected of stealing cars.
"Everything will be done to find [the suspect's] accomplices," Mr Sarkozy said.
Mr Sarkozy said Mr Nerin was the first French policeman to have been killed by Eta.
Eta is blamed for the deaths of more than 800 people since the late 1960s in its campaign for an independent Basque state.
There have been frequent arrests of Eta suspects in France, often in the south-west - though last month one of the group's leaders was arrested in the north-west of the country.
Eta, which is classified as a terrorist organisation by the US and the EU, resumed attacks in June 2007 after a truce of 15 months.