Caracas, Venezuela ? Supporters of President Hugo Chavez threw eggs and fruit at the U.S. ambassador’s car Friday and motorcyclists chased his convoy for miles, at times pounding on the vehicles. The U.S. State Department accused Caracas city officials of complicity.

Venezuelan Ambassador Bernardo Alvarez was summoned to the State Department in Washington and told that Venezuela was in violation of an international convention that requires host countries to ensure the safety of foreign diplomats, department spokes-man Sean McCormack said.

Brian Penn, spokesman for the U.S. Embassy in Caracas, said Venezuelan police escorts did not intervene as a car carrying Ambassador William Brownfield was pounded and pelted. No one was hurt.

“We’re being attacked by groups of motorcyclists while we’re traveling in an embassy car,” Penn told The Associated Press by cell phone shortly before the motorcycles stopped chasing the four-car convoy.

“It’s a very violent demonstration by a small group of people who appear to be organized by the mayor’s office,” Penn said.

The Caracas mayor’s office, however, denied any involvement. “No official authorized by the mayor’s office participated,” said Luis Martinez, a spokesman for Mayor Juan Barreto.