LONDON (Reuters) - Pulling funding from the World Health Organization (WHO) is a dangerous and nonsensical move when the world is facing the health crisis brought by the COVID-19 disease pandemic, Melinda Gates said on Wednesday.

Announcing an extra $150 million of funding from The Bill & Melinda Gates Foundation to help speed the development of treatments, vaccines and public health measures to tackle the new coronavirus outbreak, Melinda Gates said the WHO was "exactly the organization that can deal with this pandemic".

"De-funding the WHO makes absolutely no sense during a pandemic. We need a global coordinated response," Gates, who co-chairs the foundation with the billionaire Microsoft co-founder Bill Gates, said in a telephone interview.

"When you're in a crisis like this, it's all hands on deck."

President Donald Trump announced on Tuesday a halt in U.S. funding to the WHO, saying it had "failed in its basic duty" in allowing the pandemic to take hold.

The Gates Foundation is the second largest donor to the WHO behind the United States. Melinda Gates said earlier that cutting WHO funding in a health crisis was "as dangerous as it sounds".

The WHO's Director General Tedros Adhanom Ghebreyesus said on Wednesday he regretted Trump's decision. He said the organisation was still assessing the impact and would "try to fill any gaps with partners".

The philanthropic Gates Foundation's new $150 million commitment brings its COVID-19 funding for the international response to date to $250 million, but Gates said any gap left in the WHO's funding would be very hard for others to fill.

Alongside support for new diagnostics, drugs and vaccines, the Gates money is primarily aimed at helping poorer countries and vulnerable populations handle the oncoming and spreading pandemic and the poverty it will cause.

"We really as a global community need to address what is now just beginning in African and South Asian countries. We see a huge need, and that's why we have more than doubled our commitment," she said.

Praising what she described as "heroic work" by local leaders and healthcare workers in poorer countries seeking to protect vulnerable communities and slow the spread of COVID-19, Melinda Gates said the world's response to the pandemic "will not be effective unless it is also equitable".

"Whenever a health crisis hits like this, it's the people on the margins that it hits the very most," she said. "They're the ones we need to help to ensure things like cash transfer payments are made and they have access to primary healthcare."

There are currently no effective vaccines, drugs or other immune system treatments approved to treat COVID-19, the disease caused by the new coronavirus.

The $150 million of extra funding adds to an initial $100 million from the Gates Foundation designed to kick-start scientific and public health projects.

Gates said the Foundation is backing eight projects seeking potential solutions for COVID-19 vaccine development and has co-funded enhanced virus detection capacity in Africa as well as contributing to the response in China.

(Reporting by Kate Kelland, editing by Mark Potter)