'The police fired tear-gas and many demonstrators were arrested in Abeokuta,' a police officer there said by telephone.
Beko Ransome-Kuti, head of the Campaign for Democracy movement, said in Lagos he had received reports of up to 50 people arrested in clashes between police and demonstrators in the south-western cities of Abeokuta, Akure and Ilorin.
He said the protests were part of an ongoing campaign against a big fuel price increase introduced by the interim civilian government ousted this week and the annulment of presidential elections in June to end military rule.
Most people in Nigeria's biggest city, Lagos, stayed at home a day after the new military ruler, General Sani Abacha, put the country's seven-year march to democracy back to zero.
Banks, major shops and factories remained shut after General Abacha declared in a broadcast lasting barely 10 minutes that he would brook no trouble from any quarter. He banned politics, dismantled all democratic institutions and declared: 'We will not condone nor tolerate any act of indiscipline. Any attempt to test our will, will be decisively dealt with.'
Traffic remained light with few public buses on the roads. Lagos residents said the paralysis of Nigeria's commercial capital was due to the fuel price strike by workers and pro-democracy groups as well as general anxiety over the reversion to military rule.
General Abacha scrapped Nigeria's two political parties and all elected institutions in the most sweeping changes for a decade. He appealed to workers to call off their strike over a 600 per cent increase in fuel prices, imposed by the unelected stop-gap government of Ernest Shonekan in which he served as defence secretary and which he replaced.
The strike will be his first major test. He promised to look into the issue, and said: 'We cannot afford further dislocation and destruction of our economy.'
The United States has condemned General Abacha's takeover. Britain said it was urgently consulting with other countries on what further steps to take.