TUNIS, Tunisia (AP) _ The government said Friday that it arrested three Libyan saboteurs late last month before they could go into action in Tunisia.

Tunisia's minister for state security, Zine el-Abidine Ben Ali, also told a news conference that approximately 50 Tunisians recently expelled from Libya were being questioned. He did not elaborate.

The three Libyans were shown on videotape to reporters. One of the three, Sabri Mohamed Mahmoud Najeh, 34 - the only one to be identified - provided an account of what he said was his mission.

Najeh said he was a chief sergeant in the Libyan police and was sent to Tunisia on orders of Hosni Louhichi, said by Tunisian authorities to be ''responsible for the Liason Bureau of Revolutionary Committees charged with physically eliminating Libyan opposition.''

Najeh said on videotape he intended to blow up two gas stations and put a bomb in a hotel in the southern Tunisian towns of Zarzis and Djerba.

Ben Ali told reporters Najeh then intended to go to Athens, Greece, and on to Cairo, Egypt, where he was to assassinate Abdehamid Baccouche, a former Libyan prime minister.

Najeh said he was arrested Aug. 24 in the Zarzis region, 372 miles south of Tunis, in possession of a suitcase filled with explosives.

His contact in Tunisia was identified as Ali Lasfar, one of 30 Libyan diplomats recently expelled from Tunisia as part of a growing crisis between the two countries.

The crisis was touched off when Libya began huge expulsions of foreign workers in August, most of them Tunisian.

Tunisia said it was a deliberate attempt to undermine Tunisia, which has high unemployment and can ill afford the 30,000 workers sent home.

Libyan troops began gathering on the Tunisian border and the Tunisian army was placed on full alert.

Kuwait and Morocco stepped in, and the expulsions slowed down. However, there has been no hint of an accord between Libya and Tunisia.