TIMISOARA, ROMANIA, DEC. 16 -- The Rev. Laszlo Tokes, the ethnic Hungarian priest whose arrest sparked Romania's bloody revolt last December, today joined anti-government crowds in Timisoara calling for a "second revolution."

A crowd of more than 8,000 marched through the streets and gathered in Timisoara's Opera Square to commemorate the anniversary of the first street demonstrations that resulted in the ouster of Communist dictator Nicolae Ceausescu on Dec. 22 and his execution on Christmas Day.

In the capital of Bucharest this evening, several hundred anti-government demonstrators occupied central University Square, shouting demands for the resignation of President Ion Iliescu before being dispersed by about 300 club-wielding police, the Associated Press reported.

Tokes, speaking outside his church near Opera Square, said Romanians, to achieve democracy, needed a "second revolution" against Iliescu's government, which was elected in May and is dominated by former Communists.

Tokes, a dissident pastor known for his campaigns for the rights of Romania's 1.7 million ethnic Hungarians during Ceausescu's rule, urged that the revolution be "apolitical" and peaceful. Meanwhile, the crowd chanted, "The only solution is a second revolution" and "Twelve months of lies!"

In a nationwide broadcast tonight, Iliescu appealed for calm among Romanians, many of whom have dropped support for his National Salvation Front government because of continuing economic hardships and fear of former Communists in his administration.

"To negate the results of the elections only six months after they were held and impose something else in the name of a dissatisfied minority . . . would only amplify our difficulties," he said.

Iliescu also congratulated Timisoara for its courage last December, when residents sparked the revolution that ended Ceausescu's 24-year reign.

The revolt began in this city of 350,000, about 300 miles northwest of the capital, when parishioners heard that Tokes was about to be arrested by Ceausescu's security police, the Securitate, and gathered around his house Dec. 16 to protect him. When secret police came and took him away the next day, violence erupted, and demonstrations spread to the capital and other cities.

The protesters here today demanded to know why the government has not moved faster to prosecute those responsible for the deaths of more than 1,000 people during last year's revolution. Sixteen people have been convicted and 39 are still on trial for the killings, and the prime minister, Petre Roman, has recently expressed dissatisfaction with the investigation.

Timisoara's students have declared an indefinite strike until Iliescu's government resigns, and 11 factories around Timisoara are striking in solidarity with the students. Six opposition parties joined forces over the weekend to ask for new elections and a coalition government. The Liberal Party leader, Radu Campeanu, gave the proposals to Iliescu on Saturday and the president promised a rapid response.

An opinion poll this month by Romania's official polling institute, IRSOP, found that Iliescu has an approval rating of 56 percent, but that his popularity has slipped as a result of price rises in November and continuing uncertainty over the fate of Ceausescu's Securitate and other issues arising from the revolution.