MIAMI (AP) — U.S. immigration authorities have detained two brothers from Ecuador who are wanted in the South American country for allegedly stealing millions of dollars from a now-defunct bank.

Immigration and Customs Enforcement spokesman Nestor Yglesias said in an email that William and Roberto Isaias were arrested Wednesday in Miami and detained pending deportation.

Ecuador's government has sought the brothers' extradition for years, but it was not clear what prompted their arrests Wednesday. Yglesias only said the men were "unlawfully present" in the U.S.

The bank, Filanbanco, was the largest in Ecuador, and its failure in the late 1990s contributed to an economic collapse. The brothers were charged with embezzlement but fled the country before trial. They were found guilty in absentia and sentenced to eight years in prison in 2012.