MEXICO CITY (Reuters) - Mexican agents are investigating companies and individuals for possible financial ties to Lebanon's Hezbollah guerrillas, the government said on Thursday. Mexico launched the investigation after receiving a tip-off from the United States about six months ago that groups in Mexico had links to a U.S. resident suspected of being involved with Hezbollah. Attorney General Daniel Cabeza de Vaca told reporters the probe has so far turned up "nothing special" and no illegal activities. "Some financial, economic relations have been found ... with some people, some companies," he said, playing down media reports of a Hezbollah operation inside Mexico. "We're not talking about a cell per se," he said during a trip to Washington. The U.S. government considers Hezbollah a terrorist organization, although its political party made major gains in Lebanon's parliamentary elections last year and it holds two cabinet posts in the government. Lebanon's ambassador in Mexico was critical of the investigation. "This is part of a fear campaign from those who believe they are fighting against terrorism," Nouhad Mahmoud told Reuters. Mexico has a large community of people of Lebanese descent, including prominent business leaders such as telecommunications tycoon Carlos Slim, the world's third richest man.