US officials say fewer illegal immigrants are trying to enter the country from Mexico amid new enforcement rules imposed in response to the coronavirus outbreak.

Acting US Customs and Border Protection Commissioner Mark Morgan says agents are encountering about half the number of migrants along the southwest border than in the month before President Donald Trump authorized the rapid expulsion of migrants under a March 21 public health order.

Total encounters in April were about 16,700.

The public health order was initially renewed for 30 days and is scheduled to expire this month. But Morgan and Deputy Commissioner Robert Perez suggested Thursday that the public health restrictions may have to stay in place longer even as the US starts to ease quarantine restrictions.

Morgan also said border agents have encountered their first two migrants with confirmed cases of Covid-19. The first was from India and was captured near Calexico, California, on April 23. The second was a man from Mexico captured this week as he tried to enter the US to seek medical attention for his illness.