WASHINGTON, May 11 (Xinhua) -- The United States said Friday that Iran is continuing its nuclear program and urged Teheran to give up the nuclear activities and return to the negotiation table.

    "They (Iranians) are continuing down the road of building centrifuges, putting the cascades together. You can talk to the IAEA about exactly what their activities are, but there have been reports about testing at least small amounts of UF6 in their centrifuges," State Department spokesman Sean McCormack said.

    The United States will continue to build up diplomatic pressure on Teheran to get the message of the international community, McCormack said.

    "What we hope is that they finally get the message that the international system is not going to become less united, it's actually becoming more united in the demand that Iran give up this pathway to a nuclear weapons program, and to come to the negotiating table," he said.

    The United States has accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program. However, Iran has said its nuclear program is for peaceful purposes only. ¡¡