U.S. Representative Tom Tancredo, a Republican of Colorado, has announced his candidacy for the 2008 Republican presidential nomination, a newspaper reported. Tancredo, a leading voice against illegal immigration, made his announcement Monday on a radio program in Des Moines, Iowa, the state that would hold the first caucuses in next year's presidential primaries, USA Today reported.

The lawmaker promised to make the fight against illegal immigration the cornerstone of his 2008 bid, the report said. "The crisis of illegal immigration threatened not only our economy and our security but our very identity," he said in a statement.

"That ends today," said Tancredo, who, with the announcement, joined a crowded field that includes better-known hopefuls such as former New York mayor Rudy Giuliani and Arizona Senator John McCain.

Born in Denver, Colorado, in December 1945, Tancredo has served as a House member since 1999. He supports deporting all illegal immigrants and has criticized a plan by the President George W. Bush, McCain and others to give some illegal immigrants a chance for citizenship.

An estimated 12 million illegal immigrants now live in the United States. A recent USA Today/Gallup Poll shows immigration ranks fourth behind the Iraq war, terrorism and corruption as an issue that Republicans want the president and Congress to address.