Iran on Tuesday expressed satisfaction over the resignation of US Ambassador to the UN, Nikki Haley.

"’New Sheriff in town’ is no longer,” tweeted Alireza Miryousefi, head of the press office at the Iranian Mission to the United Nations, in a reference to Haley’s remarks at the AIPAC Policy Conference in 2017.

“We do not know who she was or what she was about, but she was a serious problem at the UN with her uninformed statements and her causing the isolation of U.S. You need to know: there is no new sheriff in town,” he added.

Iran’s envoy to the UN, Gholamali Khoshroo, also commented on Haley’s resignation, claiming that the United States’ unilateral policies on legal, international and environmental issues and the country's withdrawal from the international agreements, including the Iranian nuclear deal, has increased its isolation in the world.

According to the IRNA news agency, Khoshroo further claimed that the United States’ unilateralism during Haley's tenure led to the US' isolation in the UN.

Despite Haley’s efforts in the UN, the Palestinian issue is still a top priority, he added.

Haley and President Donald Trump announced on Tuesday morning that she will exit the administration by the end of 2018. Trump said Haley informed him of her plans six months ago, and that she wanted to "take a break" from public service.

Haley has been an outspoken critic of the UN's corruption, bias, and inability to deal with human rights crisis around the world. She was also Israel's biggest supporter at the UN.

She was also a vocal critic of Iran, having recently warned of the danger the Iranian regime presents to the Middle East.

"The Iranian regime has backed dictators who gas their own people. It stokes conflict. It funds foreign fighters and terrorists. It transfers missiles to militants. It acts against the interests and policies of this Security Council, time and time again," she said during a meeting of the Security Council on the subject of the Middle East.