Firing into the air, unleashing tear gas and arresting a leading dissident, security forces of Nigeria's latest military boss sent an unmistakable message Friday to the nation's pro-democracy forces: Muscle still rules this junta-weary country.

Opposition activists demanding an end to military rule took to the streets in a planned mass protest, but they were quickly confronted by a wall of police and soldiers in Lagos, Nigeria's commercial hub.Throughout the city, convoys of heavily armed troops and riot police roared through the streets, firing weapons and clashing with protesters, dragging some of the demonstrators away.

Faced with his first major test - the prospect of defiant opposition - Gen. Abdulsalam Abubakar responded with enough might to quell hopes that his 5-day-old regime would differ from that of the 5-year-long military dictatorship of his predecessor, Gen. Sani Abacha.

"We want the world to know that Nigerians want an end to military rule," said one protester, University of Lagos student Dele Alabai.

"This is not about Abacha or about Abubakar. It is a struggle for democracy," the student said.

As opposition leader Gani Fawehinmi arrived at the scene of one of the protests, three men lifted him onto their shoulders, witnesses said. Police, enraged when the crowd began to cheer support for him, quickly arrested Fawehinmi, along with the men carrying him.

They also arrested Dupe Abiola, one of the wives of imprisoned businessman Moshood Abiola, the presumed winner of canceled 1993 elections.

Fawehinmi was later released on bond. It was unclear whether the others were as well.

Fawehinmi has been detained before and released, but his arrest Friday hit hard at an opposition already weakened by the imprisonment or exile of most of its main leaders.

"We are very bitter about what has happened," said Fawehinmi's son and aide, Mohammed Fawehinmi.

With Abacha's death Monday from a heart attack, Nigerians had been hopeful that the country's next leader might see the transition as an opportunity for democratic reform. But the crackdown Friday suggested the new regime is picking up where the old left off.

"Soldiers are all the same," said Joseph Ahmed, a Lagos resident watching police haul away a few protesters from the scene of one confrontation. "If anyone wants to criticize them, they go and use force."