Adolfo Aguilar Zinser, Mexico's former ambassador to the United Nations, has died in an automobile accident in central Mexico.

Authorities in the state of Morelos say the 55-year-old ex-diplomat was driving on a highway Sunday when his vehicle hit a bus.

Mr. Aguilar Zinser was a vocal opponent of the U.S.-led invasion of Iraq during his tenure at the UN. Mexican President Vicente Fox removed Mr. Aguilar Zinser from the UN post after he accused the United States of treating Mexico with disdain.

Mr. Aguilar Zinser spent years as a leftist politician in the Mexican legislature. But he later joined forces with the conservative Fox, and played a key role in Mr. Fox's historic election in 2000.

He served Mr. Fox as national security advisor before taking the UN post.

Some information for this report provided by AFP and AP.