(AFP) - The United States said Monday it is bolstering precautions to prevent the spread of Ebola, including screening air travelers from outbreak-hit areas and temporarily suspending visa services.

The measures shared by the US Centers for Disease Control and Prevention (CDC) come as the World Health Organization has declared the deadly Ebola outbreak in the Democratic Republic of Congo (DRC) an international health emergency.

In a briefing, Satish Pillai, the health agency`s Ebola response incident manager, told journalists one American in the DRC had contracted the virus following exposure related "to their work" there.

"The person developed symptoms over the weekend and tested positive late Sunday," Pillai said, adding that efforts were underway to transport the individual to Germany for treatment.

The official added the United States was attempting to evacuate six additional people for health monitoring.

Pillai said there are about 25 people working in the US field office in the DRC, and that the CDC was fulfilling a request to send an additional senior technical coordinator.

"At this time, CDC assesses the immediate risk to the general US public as low, but we will continue to evaluate the evolving situation and may adjust public health measures as additional information becomes available," the health agency said in a statement.

In addition to screening at airports, the CDC said it was implementing entry restrictions on non-US passport holders if they had traveled to Uganda, DRC or South Sudan within the past 21 days.

The US Embassy in Kampala, Uganda, said it had temporarily paused all visa services, and that impacted applicants had been notified.

Trump said he was "concerned" by the outbreak but that "I think that it`s been confined right now to Africa."

- Criticism of US response -

There is no vaccine or specific treatment for the strain responsible for the current spread of the highly contagious hemorrhagic fever.

Ninety-one reported deaths are suspected to have been caused by the current surge in cases, according to the latest figures released on Sunday by Congolese Health Minister Samuel-Roger Kamba.

Around 350 suspected cases have been reported. Most of those affected are aged between 20 and 39 and more than 60 percent are women.

The United States under President Donald Trump formally withdrew from the World Health Organization (WHO) this year.

In recent days, US officials have avoided questions about how the administration`s cutting of the US Agency for International Development (USAID) -- key in responding to previous Ebola outbreaks -- has impacted current efforts to monitor and manage the virus`s spread.

CDC officials have emphasized they are collaborating with international partners and health officials in impacted countries.

The public health measures announced Monday will include continued "deployment of CDC personnel to support outbreak containment efforts in affected regions" as well as assistance with contact tracing and laboratory testing, the agency said.

And the US State Department said in a statement Monday it had mobilized $13 million in aid for "immediate response efforts."

But Matthew Kavanagh, director of the Georgetown University Center for Global Health Policy and Politics, said the US response thus far was "disappointing" and called travel bans "more theater than effective public health measures."

"The administration claimed it could negotiate bilateral deals and replace the capacity of WHO with domestic efforts. This outbreak clearly shows that is a failed strategy," he told AFP.

He said during previous Ebola outbreaks, coordinated efforts between USAID, the CDC and US-funded nonprofits led to rapid response and containment.

This time, "we`re weeks into an outbreak and only finding out about it after hundreds of cases and major spread including to the capital city of Uganda," Kavanagh said, adding that the Trump administration was "playing catch-up."