TEHRAN, Iran (AP) — University students threw stones and burned tires during a riot early today in a sign of growing public anger at a hard-line crackdown that has shut down 16 reformist newspapers.

About 200 students took part in an overnight protest at Tehran's Shahid Beheshti University that turned violent in the early hours, a journalist at the scene told The Associated Press.

Police and hard-line vigilantes dispersed the protesters after an hour of rioting in which demonstrators burned tires and threw stones at college buildings, he said on customary condition of anonymity. Some protesters were detained but later released, he said.

The hard-line crackdown on the media was triggered by their rout in the February legislative election, which sent a clear signal that the pro-democracy reforms of President Mohammad Khatami have gained nationwide popularity and acceptance.

Reformist candidates won about 70 percent of seats contested, but hard-line authorities annulled 12 reformist victories. They also said there might be changes in the capital of Tehran where reformists won 29 of the 30 seats, alleging fraud and inconsistencies.

A second-round election to decide 66 seats in the 290-member parliament, or Majlis, will be held May 5. A reformist dominance of the legislature was expected to boost Khatami, a moderate cleric who came to power in 1997.

Despite hurdles, he has eased many of the social, political and cultural restrictions that the clerical government has imposed since taking over in the 1979 Islamic revolution. Khatami's cause has been championed by the reformist papers.

Without support from the press, reformist lawmakers and candidates might have to wait until parliament resumes session May 27 to restart direct dialogue with the people: The constitution mandates that Majlis debates be broadcast live on state radio.

"The reformists are under siege. They are looking to the opening of the Majlis as the cavalry," said Saeed Laylaz, an analyst who used to write for the Azad daily before it was closed down Monday with a court order issued by the hard-line judiciary.

After this week's crackdown, only one reformist newspaper, Bayan, remained on the stands because it has not been so outspoken as the others. Sixteen other newspapers were banned by the hard-line controlled judiciary, including the Mosharekat newspaper published by Khatami's brother Mohammad-Reza Khatami.

Two reformist journalists, Akbar Ganji — Iran's leading investigative reporter — and Latif Safari, also have been arrested.

Despite the pressure, Khatami was quoted Thursday on Iranian TV as saying everyone should "act within the framework of the law in order to calm the crisis and meet the needs of society."