VENICE, Italy — A stellar American profile and heavy security distinguish this year's Venice Film Festival, which began Wednesday night with a martial arts extravaganza, Tsui Hark's "Seven Swords."

Metal detectors were just about everywhere and bomb-searching police divers worked the waters off the Lido, Venice's beach section where the festival is being held. Security concerns about a possible terrorist attack resulted in fewer films this year — 56 instead of the 70-plus in past years.

Organizers boasted about an unprecedented nine world premieres of U.S. films, including "Good Night, and Good Luck," considered a top contender for the fest's top award — the Golden Lion.

The black-and-white film directed by George Clooney is a serious look at America a half-century ago when there was an attempt to root out communist sympathizers. Clooney plays a bold CBS producer, Fred Friendly, and David Strathairn is Edward R. Murrow, the broadcast pioneer who challenged the crusade of Sen. Joseph McCarthy.

Clooney, whose love affair with his northern Italian lakeside villa practically gives him hometown status, is expected at the Lido for Thursday's screening.

Another U.S. actor on the other side of the camera here is John Turturro, in competition with "Romance and Cigarettes" — a musical love triangle featuring Susan Sarandon, Kate Winslet and James Gandolfini.

Other films being touted include Ron Howard's "Cinderella Man" starring Russell Crowe, and Ang Lee's "Brokeback Mountain," about a homosexual relationship between two 20th century American cowboys.

Nineteen movies are competing for the Golden Lion at this year's festival, including Terry Gilliam's "The Brothers Grimm," John Madden's "Proof" and Abel Ferrara's "Mary."

What's Venetian in all this?

Giacomo Casanova, the 18th-century Venetian libertine whose bold life is the subject of Lasse Hallstrom's "Casanova."

Also being shown: a restored version of Federico Fellini's 1976 version starring Donald Sutherland.

The festival ends Sept. 10 with Peter Ho-Sun Chan's "Perhaps Love."

The festival also attracted demonstrators — a motley, noisy group of about 2,000 people dressed in shorts and bikinis who were held at bay by police officers in riot gear Wednesday evening. The demonstrators shouted slogans against imperialism, blew horns and lit fire crackers and claimed they represented "the cinema of the forbidden."