Playwright Vaclav Havel Tuesday was convicted and sentenced to nine months in prison for his role in a rally commemorating a student who killed himself to protest the 1968 Soviet-led invasion.

Havel, Czecholovakia's best-known dissident, denied charges that he incited people to "anti-state and anti-Socialist" activity.In the one-day trial, he was convicted of inciting participation in the banned Jan. 16 rally and for obstructing the duty of a public official.

On the first count he could have been sentenced to a maximum term of two years, on the second to another six months in prison. Prosecutors had asked for a one-year term, but Judge Helena Hlavata ruled on a nine-month prison term and rejected a proposed fine.

The prosecution of Havel and other opposition activists has gone on despite widespread criticism at home, in the East bloc and the West that the communist leaders are dealing too harshly with dissent. Seven other activists from the Charter 77 human rights committee and other independent movements also went on trial Tuesday.

Authorities banned a number of Western diplomats and representatives from human rights organizations from the trials.

Havel, 52, who helped found the Charter 77 movement, has been harassed and detained by authorities almost constantly since his 1975 open letter to Communist Party leader Gustav Husak accused authorities of creating "a bureaucratic order of gray monotony that stifles all individuality."

Havel was convicted of sedition and sentenced to four years in jail in 1979. Authorities have banned his plays, which are widely acclaimed in productions abroad.

Havel's brother, Ivan, said Havel did not take part in a Jan. 16 flower-laying ceremony in a downtown Prague square but was detained on the square an hour later.

The seven other defendants - all activists with Charter 77 and other independent groups - face hooliganism charges in connection with the Jan. 16 gathering. The charges carry a maximum two-year jail sentence.