Homeland Security Secretary Janet Napolitano says the U.S.is closely monitoring the activities of Iran-linked militant group Hezbollah.

Napolitano told lawmakers Wednesday that the Homeland Security Department has contacted Jewish organizations around the country and is working with the FBI and other law enforcement and intelligence agencies. She said there is no specific or credible threat against any organization or target in the United States, which considers Hezbollah a terrorist group.

Iran has been accused of launching a series of attacks against Israeli interests this week in Thailand, Georgia and India. Hezbollah is closely allied with Iran. The Defense Department estimates that Hezbollah receives between $100 million and $200 million a year in funding from Iran.

Napolitano said the threat from Hezbollah remains a "critical situation worth watching."