That was the question being asked today after French police said that three masked raiders who kidnapped the daughter-in-law and grandchildren of an arms warehouse manager in Nimes, were probably from the group. The trio consisted of two men and one woman.

The abductors forced the female manager to open up the warehouse on Tuesday and took away around 350 pistols.

"Everything leads us to believe that it was Eta," Nimes public prosecutor Robert Gelli said.

He cited "the mode of operation, the presence of a woman, the foreign accent of the individuals ... and of course, the nature of the objects stolen."

After loading up the weapons into their vehicle, the robbers tied the manager up. She escaped hours later, Gelli said.

The manager's daughter-in-law and two grandchildren - one aged seven and one aged nine months - were held overnight in a car in a nearby village. They broke free early the next day.

Spanish media reported that handcuffs taken off two French police officers by pistol-wielding Eta members in March had been used in the attack.

If confirmed, the robbery would be the first such act by Eta since it called the ceasefire on March 22.

The group, which has historically only carried out attacks in Spain, has killed more than 800 people over the past four decades.

Over the past five years, however, police action both in Spain and France - where its command and logistics structure are traditionally based - has weakened it considerably.

Many saw its truce declaration as an attempt to negotiate a dignified exit from violence after more than two years in which, despite its efforts, it failed to kill anyone at all.

Most Spanish Basques, and most Spaniards, had hoped the ceasefire meant violent attempts to create a separate Basque were over.

The robbery comes as the Basque peace process was already going through a sticky patch.

Some 40 leading members of Batasuna, a banned separatist political party which is heavily involved in the process, and other separatist groups were formally accused with being Eta members on Tuesday.

Police acting on the orders of the supreme court began registering dozens of separatist social clubs and bars on Monday in San Sebastián, Bilbao, Vitoria, Durango and elsewhere. The bars are also considered to be involved with Batasuna.

Outside one such bar in Bilbao, around 50 protesters gathered carrying placards with slogans such as "You will not stop us", or "Get out of here and leave us alone."

The socialist prime minister, José Luis Rodríguez Zapatero, has repeatedly warned that the peace process will be long and difficult. He received unexpected support from Tony Blair during a visit to Madrid earlier this month.

"My experience of this is that sometimes there appears to be a blockage or you get diverted from the path you want to take," Mr Blair said.

"But on the other hand, if the will is there and people apply the right type of what I call patient determination, in other words, understanding, if you are always doing the best, it does happen," he added.

Unlike the Northern Irish peace process, however, there is no cross-party support for Mr Zapatero.

He is having to go ahead with the peace process without the backing of the opposition conservative People's party, which accuses him of selling out to murderers.

Unconfirmed newspaper reports suggest that socialist government representatives and Eta leaders have been meeting secretly in Norway over recent weeks.

Mr Zapatero has suggested to Batasuna that it might, in effect, become legal again if its members founded a new party.

That was rejected by Batasuna, however, which wants to be able to stand again at elections with its old name.

For the process to advance, proposed talks on the Basque region's future - bringing together pro-independence parties and mainstream ones favouring the status quo - must begin right away, the banned party said in a statement last week.

"Everything else are exercises in distraction and diversion," the statement said.

Batasuna made no mention, however, of denouncing Eta's violence as a condition for regaining legal status and taking part in the all-party talks, as demanded by Mr Zapatero.

Tuesday's robbery now opens the possibility that Eta is rearming, and that it has run out of patience with peace.