The United States cut a $2 million pledge for the United Nations Counterterrorism Office on Wednesday and downgraded its presence at a conference on the issue, the Trump administration's latest move to use funding to push for reform of the world body.

The funding cut was made over a decision by the U.N. counterterrorism chief, a former Russian diplomat with more than 30 years service, to close part of an inaugural conference to nongovernmental interest groups, a U.S. official speaking on condition of anonymity said.

When asked if the decision had anything to do with counterterrorism chief Vladimir Voronkov being Russian, the U.S. official said "it matters" and that Voronkov had come under "tremendous pressure by his home country" on the conference.

Voronkov's office did not immediately respond to a request for comment.

U.S. Ambassador to the United Nations Nikki Haley said in a statement that there was no precedent for excluding the interest groups, known as "civil society," from a conference hosted by the U.N. Secretary-General in the General Assembly.

"There is no reasonable explanation for why the UN would seek to censor this conference, except that it caved to political pressure from a handful of nefarious countries with no credibility on countering terrorism – like Russia, Syria, Iran, Cuba, and Venezuela – and for which restricting access and blocking civil society participation is the norm," Haley said.

Russian President Vladimir Putin's government has been accused by Western countries of cracking down on interest groups and discouraging independent institutions.

The U.S. official said the United States and other countries had pushed U.N. Secretary-General Antonio Guterres and Voronkov, who was appointed a year ago, to include the groups in the whole conference because they have valuable contributions to make.

The U.S. stance on the one-year old office is the latest salvo in the Trump administration's push for change at the U.N. Last week, the United States withdrew from the U.N. Human Rights Council over what it saw as the body's bias against Israel and a lack of reform.

Two sessions at the counterterrorism conference's opening day on Thursday - on the sharing of information and expertise and combating foreign fighters - will be closed to interest groups and media.

A senior U.N. official, also speaking on condition of anonymity, said the reason for the closures was the expectation of "a lot of sensitive information shared between the heads of counterterrorism agencies."

The U.S. official said Washington has downgraded its representation at the two-day conference to an acting deputy coordinator in the State Department Bureau of Counterterrorism, instead of a possible ministerial level official.

Nearly 120 countries were expected to attend, along with 100 civil society groups, the U.N. official said. Close to 75 percent of delegations would be led by heads or deputy heads of counterterrorism agencies or interior ministers, the official said.