SEOUL, South Korea — North Korea has told the World Health Organization that it has tested 25,986 people for the coronavirus through April but still has yet to find a single infection.

The WHO said in a weekly monitoring report that North Korea’s testing figures include 751 people who were tested during April 23-29, of which 139 had influenza-like illnesses or severe respiratory infections.

Experts have expressed skepticism about North Korea’s claim of a perfect record in keeping out COVID-19, given its poor health infrastructure and a porous border it shares with China.

North Korea has described its anti-virus efforts as a “matter of national existence.” It has barred tourists, flown out diplomats and severely restricted cross-border traffic and trade.

The North has stopped providing the number of people it quarantines this year, but previously said it had quarantined tens of thousands who had exhibited symptoms.