CARACAS, Venezuela (AP) _ Mobs angered by a public transportation strike looted a dozen grocery stores and burned a truck, a TV news program reported. Rock-throwing students battled police in Caracas.

At least 50 people were reported arrested.

The disturbances Tuesday in seven cities were among the worst since February 1989, when 300 people were killed and more than 1,000 injured in widespread rioting over an increase in bus fares.

In the cities of Barcelona and Puerto La Cruz, both about 120 miles east of Caracas, at least 12 grocery stores where sacked before police fired tear gas to disperse the mobs, Radio Caracas Television said.

No casualties were reported during the violence but at least 30 people were arrested in both cities, the TV reported.

At least 20 students were arrested after a two-hour battle with police in a square outside Venezuelan Central University in Caracas, witnesses said.

The students threw rocks and set a truck on fire, students said.

Minor disturbances broke out in Merida, Cumana, San Cristobal, Barquisimeto and Maracaibo, police sources said.

Many of the protesters were students angered by the strike and by the refusal of some bus lines whose to grant student discounts. The strike left most cities with only partial public transportation.

The strike was called by unions protesting delays by the government in paying subsidies that allow discounts of up to 50 percent over regular rates for students.

Increases of 30 percent to 50 percent in public transport tariffs and price gouging by bus drivers set off the rioting in February 1989 - the worst violence in Venezuela in 31 years.

The nation of 18 million had been regarded as an island of tranquility in a region of increasing violence and political and economic instability.

The price increases were part of a government austerity program intended to halt the downward economic spiral that has gripped Venezuela since the collapse of oil prices in the early 1980s.

The Caracas-based Latin American Institute for Social research surveyed 2.3 million families in 1981 and classified 22.5 percent of them as poor. In 1987, it surveyed 3.1 million families and categorized 54 percent of them as poor.