JERUSALEM, JUNE 4 (AP/UNB) - A senior U.S. official says sanctions on Iran are biting, but more will be done to pressure the Islamic Republic over its nuclear program.

Deputy Secretary of the Treasury David Cohen told Israel's Army Radio on Monday, "The sanctions are having an impact on Iran, but I also recognize that more needs to be done. And we are intent on doing more."

Cohen is Washington's point man on pressuring Iran over its suspect nuclear program. Iran claims the program is designed to produce energy and medical isotopes, but Israel and world powers say Tehran is secretly working on building bombs.

Cohen is visiting Israel two weeks ahead of the next round of nuclear talks between world powers and Iran in Moscow.