London's Heathrow airport closed early Monday due to a new volcanic ash cloud from Iceland, the U.K.'s leading air navigation services provider NATS reported.
Heathrow closed at 1 a.m. local time (midnight GMT) on Monday until at least 6:00 GMT.
"The high density ash cloud continues to move further south," NATS said in a statement.
"For the period 0100 (local time) until 0700 tomorrow (Monday), airports inside the no-fly zone as imposed by the CAA, include: London Heathrow, Gatwick, Farnborough, London City, Shoreham, Biggin Hill, all airfields in Northern Ireland, Scottish Western Isles, Oban, Campbeltown, Caernarfon and Aberdeen," NATS said.
"Cardiff remains open but operations may be limited due to close proximity of the no-fly zone," it said.
The eruption on the Eyjafjallajokull Glacier in Iceland, which began April 14, paralyzed air traffic throughout central and northern Europe, leaving thousands of travelers stranded and forcing more than 20 European countries to close their airspace.
During the three most serious days of disruptions (April 17-19), European airlines' lost revenues reached $400 million per day. Flights resumed across Europe on April 21.