Iran went on the offensive against the Obama administration on Thursday, accusing Washington''s new U.N. ambassador of making the "same tired" accusations against Iran as the Bush administration.

In a speech to the Security Council during a session on Iraq, U.S. envoy Susan Rice reiterated charges of Iranian support for terrorism and attempts to develop nuclear weapons, saying the United States sought an end to both policies.

"It is unfortunate that, yet again, we are hearing the same tired, unwarranted and groundless allegations that used to be unjustifiably and futilely repeated by the previous administration," Iran''s envoy Mohammad Khazaee said in a letter to the council''s president, Japanese Ambassador Yukio Takasu.

"Instead of raising allegations against others, the United States had better take concrete and meaningful steps in correcting its past wrong policies and practices vis-a-vis other nations, including the Islamic Republic of Iran."

Khazaee''s remarks were among the most critical of the new U.S. administration by a senior Iranian official. Iran is not in the Security Council and no Iranian official attended the meeting at which Rice spoke.

The comments on Iran by Rice, who sits in the cabinet of President Barack Obama, were made almost in passing during a periodic Security Council review of U.N. activities in Iraq.