Experts and other witnesses appearing before a congressional committee say Iran continues to support terrorist groups and is encouraging instability in Iraq.  A hearing also included emotional testimony by individuals affected by Iranian-backed terrorism.

From Israel and the Palestinian territories to Iraq and elsewhere, witnesses at Wednesday's hearing said Iran's ongoing sponsorship of terrorism is indisputable, and poses a direct and continuing threat to U.S. interests.

Matthew Levitt, of the Washington Institute for Near East Policy, says this support is wide ranging, but has focused on undermining efforts to achieve peace between Israelis and Palestinians:

"Iran and its proxies are intent in undermining the best chance for progress toward peace since peace talks crumbled in 2000,? said Mr. Levitt.  ?Hezbollah, Hamas, Islamic Jihad, al-Aksa Martyrs and others all at Iran's behest, are currently attempting to torpedo the nascent peace process."

Most notable, in Mr. Levitt's view, is Iran's support for the radical terrorist group Hezbollah, and its targeting of Israel as well as Americans.  He adds there is substantial evidence Iran is also behind terrorism in Iraq.

"Iranian and Hezbollah elements are very active today in Iraq,? he stated.  ?While Iranian ministers have asserted that Tehran has not encouraged the Iraqi insurgency or permitted suicide bombers to cross the border, their actions indicate otherwise."

Republican Congresswoman Ileana Ros-Lehtinen says Iran's support for Hezbollah reflects Tehran's determination to oppose U.S. interests:

"Hezbollah has helped Iranian interests through continued terrorist attacks against the United States and our allies in the region," she said.

Among witnesses at the hearing was an American who was one of 65 people taken hostage by militants at the U.S. Embassy in Tehran in 1979 after the fundamentalist takeover by Ayatollah Khomeini.

Former hostage William Daugherty says the record of Iran's regime since then underscores a very real threat to Americans.

"Convinced that it need have no fear of retribution or penalty, terrorism has been and remains a central component in the foreign policy of the Islamic Republic," he said.

Mr. Daugherty says Congress should press the Bush administration to, in his words, back up U.S. rhetoric with concrete action.

There was also this emotional testimony from Lynn Smith Darbyshire, whose brother Vince was killed in the bombing of the U.S. Marine barracks in Beirut in 1983, an attack carried out by the Iranian-sponsored Hezbollah.

"The government of Iran has been perpetrating acts of terrorism and supporting terrorist organizations long enough.  We need to stop them,? she said.  ?We need to everything in our power to deter future acts of terrorism, so that other little girls will not have to watch their brothers die."

The joint hearing of two House subcommittees dealing with the Middle East and terrorism followed separate testimony earlier by other experts on options the United States, European Union, and others have in dealing with Iran's nuclear development efforts.