Morocco is halting flights to and from Britain, Germany and the Netherlands due to concerns over the spread of COVID-19 in those countries, official sources in the North African kingdom said Wednesday.

Flights will stop from 11:59 p.m. (10:59 p.m. GMT) Wednesday "until further notice,",the national airports office (ONDA) said on Twitter.

National carrier Royal Air Maroc said the decision was "due to the evolution of the pandemic" in these three European countries.

Earlier this month, Rabat suspended air links with Russia for the same reason.

Russian President Vladimir Putin on Wednesday ordered a nationwide weeklong paid holiday to curb COVID-19 infections.

Britain on Tuesday said it was monitoring a subvariant of the delta strain of the novel coronavirus, seen in a growing number of cases in the country.

Prime Minister Boris Johnson's spokesperson said the government was keeping a "close eye" on the AY.4.2 variant but said there was no evidence it spreads more easily.

Overall infection rates in Britain remain stubbornly high, despite high rates of vaccination.

Infection rates in Germany and the Netherlands have risen recently.

Morocco, a country of around 30 million people, has officially recorded more than 940,000 COVID-19 cases and more than 14,500 deaths.