London ? Two of Europe’s busiest airports closed early this morning as a dense cloud of volcanic ash drifted from Iceland, aviation authorities said.

The airspace over London’s Heathrow Airport closed at 1 a.m. local time today, Britain’s National Air Traffic Service said in a statement late Sunday night.

In Amsterdam, Schiphol Airport, another of Europe’s biggest air travel hubs, was closed until 2 p.m. local time today, a statement on Dutch airline KLM’s website said.

The restrictions affecting Heathrow — as well as Gatwick, Stansted and London City airports — will be in place until at least 7 a.m. local time today, the aviation authority said.

Airports across Britain and Ireland were closed for much of Sunday because of the drifting ash. The shifting of the no-fly zone southward will allow airports in northern England — including the key cities of Manchester and Liverpool — to reopen after 1 a.m. local time.

But all airports in Northern Ireland, as well as some Scottish facilities, will remain shut.