WASHINGTON (Reuters) - The White House expressed disappointment Monday in Iran's pledge to limit cooperation with the U.N.'s nuclear watchdog over its nuclear program.

The U.N. Security Council imposed arms and financial sanctions on Iran Saturday for its refusal to suspend nuclear work. Key nations at the same time offered new talks and renewed an economic and technological incentive package offer.

Iran said in response it would partially suspend cooperation with the U.N. International Atomic Energy Agency and called the sanctions illegal.

"Considering the international community is united in its desire to work with Iran on a solution, their comments are disappointing," said Gordon Johndroe, spokesman for the White House National Security Council.

The United States suspects Iran is trying to develop a nuclear weapon, a charge Tehran denies.