Washington DC - The US announced Wednesday that it had allocated more than $242 million in additional funding to combat the worsening Ebola outbreak in the Democratic Republic of Congo.

The new funding brings direct US financial assistance in response to the outbreak to more than $500 million, the State Department said in a statement, underlining that the US remained "the largest financial contributor to the Ebola response."

Washington called on other countries to increase their contributions to efforts to combat the disease.

The US has faced criticism over its strict travel restrictions put in place to prevent Ebola entering the country, as well as the establishment of a quarantine center in Kenya for US citizens, a move challenged in court in that country.

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The announcement of the new funding came as the head of the World Health Organization arrived in the DRC, an organization representative said Wednesday.

The DRC, a vast central African nation of more than 100 million people, declared its 17th Ebola outbreak on May 15, several weeks after the disease was believed to have begun spreading.

The WHO warned Saturday that the outbreak was spreading at an "exceptional pace" and called for the health response to be stepped up.

DRC authorities have reported a total of 3,874 confirmed cases, including 1,751 deaths, since the outbreak began.

Washington on Wednesday also praised measures taken by Uganda to contain the outbreak.

"While the trajectory of the outbreak in the DRC remains concerning, the United States commends Uganda for swift and decisive action to respond to the outbreak and limit the spread of Ebola," the State Department said.

The US has imposed Ebola-related travel restrictions on travelers arriving from the DRC, Uganda, and South Sudan. US authorities also prohibit their citizens from traveling directly from the DRC to the US.