The United States intelligence chief John Negroponte had warned that Iran was using "terrorist" operations abroad as a key element of its national security strategy.
A day after President George W Bush warned that US soldiers in Iraq would act against Iranian and Syrian elements in the war ravaged country, the director of national intelligence said Shiite militant group Hezbollah was acting as a key agent for Tehran.
"We assess that Iran regards its ability to conduct terrorist operations abroad as a key element of its national security strategy," Negroponte said.
"It considers this capability as helping to safeguard the regime by deterring US or Israeli attacks, distracting and weakening Israel, enhancing Iran's regional influence through intimidation, and helping to drive the US from the region," he said.
Negroponte, who has been named deputy to Secretary of State Condoleezza Rice, said that at the "center" of Iran's "terrorism strategy" was Lebanese Hezbollah, "which relies on Tehran for a substantial portion of its annual budget, military equipment, and specialized training."
He said that Hezbollah was focused on its agenda in Lebanon and supporting anti-Israeli Palestinian "terrorists."
The spy chief also said that Iranian conventional military power threatened Persian Gulf states and challenged US interests.
"Iran is enhancing its ability to project its military power, primarily with ballistic missiles and naval power, with the goal of dominating the Gulf region and deterring potential adversaries," he said.