The United Nations’ second-highest ranking official, Amina Mohammed, has been accused by an advocacy group of allowing illegal exports of endangered timber from Nigeria to China when she was environment minister in the West African nation. She has denied any wrongdoing.

The Environmental Investigation Agency said that 1.4 million logs of Nigerian rosewood worth $300 million were confiscated for months by Chinese authorities upon arrival at ports, pending paperwork. They were released after Mohammed provided in January 2017 permits retroactively issued to clear their export from Nigeria. This was just weeks before she left her ministerial post to join the UN, the EIA said in a report released Thursday after a two-year investigation.

Mohammed, the UN Deputy Secretary-General since February 2017, “appears to have signed thousands of retroactive CITES documents that legalized the timber,” Washington, DC-based EIA said, referring to the Convention on International Trade in Endangered Species of Wild Fauna and Flora, to which Nigeria is a signatory.

Mohammed “categorically rejects any allegations of fraud” and has Secretary-General Antonio Guterres’ full support, a UN spokesman said Friday in an emailed response to questions.

Luxury Furniture

Officials in Nigeria allegedly received more than $1 million in bribes from Chinese rosewood importers, according to the EIA, who did not give their names. A spokeswoman at the environment ministry said Friday she wasn’t immediately able to comment on the report.

A growing Chinese demand for West African rosewood, used for luxury furniture, led to the listing in May last year of the timber as an endangered species by the CITES, the report said.

Mohammed was an adviser to former UN chief Ban Ki-moon before returning home to take the appointment as minister of environment from November 2015 to February 2017, when she became Guterres’ deputy.

As minister, Mohammed laid the groundwork for Africa’s biggest crude producer’s first sovereign green bond, to be issued next month, and advocated for multinational oil companies to pay to clean up pollution in the oil-producing Niger River Delta region.