Madrid - Thousands of Spaniards around the country Thursday staged silent rallies to protest the killing of entrepreneur Ignacio Uria by suspected members of the militant Basque separatist group ETA.

Uria, 71, was gunned down in Azpeitia in the Basque region on Wednesday.

ETA was believed to have targeted him as one of the heads of a company participating in the construction of a high-speed railway which the group opposed on ecological and political grounds.

Protesters gathered in front of city halls while parliament and regional institutions also observed a moment of silence.

The law and the legal state were "weapons" which would finish with the "murderous madness" of ETA, Deputy Prime Minister Maria Teresa Fernandez de la Vega vowed.

The parliamentary parties made a show of unity against ETA by issuing a declaration pledging to fight terrorism with "courage and democratic strength."

The Basque parties Aralar and Eusko Alkartasuna meanwhile left the Azpeitia town council, because their partner Basque Nationalist Action (ANV) had not condemned Uria's killing.

ANV was outlawed for links with ETA earlier this year, but it has continued governing municipalities where it had come to power before the ban.

Spanish police had been on a raised alert against a possible attack by ETA since the arrest of the group's suspected military leader Mikel Garikoitz Aspiazu alias Txeroki in France on November 17.

ETA, which is listed as a terrorist organization by the European Union and the United States, has killed more than 820 people in its campaign for a sovereign Basque state. Uria was ETA's fourth suspected victim this year. (dpa)