Liu Xiaoming said Thursday that the international community must work together to address the crisis and urged other nations to put lives ahead of politics, according to China’s state-backed CGTN news channel.

China has been criticized for underplaying the severity of the novel coronavirus when it first appeared in the central city of Wuhan in December. Whistleblower doctors were silenced by local officials and some arrested, even as the virus spread through the city and beyond.

By the time the Chinese government notified the world of human-to-human transmission of the disease, it had already spread far beyond China’s borders.

Liu rejected accusations that Beijing had moved too slow in warning the world of the danger. He claimed the government notified the international community without delay, helping to create a “strong line of defense” for a global response.

The ambassador dismissed the criticism, and warned that “arrogance and insolence” will undermine international cooperation and put more lives at risk, CGTN reported. He added that politicizing the pandemic will damage humanity’s shared interests.

China has mounted a fierce defense of its COVID-19 response, but international skeptics remain concerned that Beijing is not being transparent about the crisis. China appears to have largely stemmed its own outbreak though remains on guard for a possible second wave of infections.

But foreign governments and researchers have suggested that the scale of the outbreak and the death toll is far higher than Beijing admits. There have so far been 83,878 confirmed infections in China and 4,636 deaths, according to Johns Hopkins University.

A U.S. intelligence report sent to the White House last month reached the same conclusion, and President Donald Trump and Secretary of State Mike Pompeo have called on the Communist Party of China (CCP) to share all available information about its coronavirus battle.

Obfuscation and delay reportedly reached the very highest levels of the CCP. According to a report by The Associated Press, President Xi Jinping knew the outbreak was likely to become a pandemic for six days before he told his citizens. Millions of people traveled inside China and abroad during this window in the run up to Lunar New Year.

China has framed international criticism as a racist effort to divert attention from poor governmental performance. Beijing has been particularly critical of the Trump administration, which is also accused of badly mismanaging its coronavirus response. The U.S. is now the epicenter of the pandemic, with 842,624 confirmed cases and 46,785 deaths as of Thursday.