Drifting clouds of volcanic ash from Iceland grounded hundreds of flights in northern Europe on Thursday, closing airspace in Britain, Germany, and Scandinavia.

Smoke billows from a volcano in Eyjafjallajokull April 14, 2010. A volcanic eruption in Iceland spewed black smoke and white steam into the air on Wednesday and partly melted a glacier, setting off a major flood that threatened to damage roads and bridges. [Xinhua]

Several British airports closed Thursday after a massive cloud of ash from an erupting volcano in Iceland drifted into Britain's airspace.

About 150 flights were canceled at Heathrow Airport，one of the world's busiest. Aberdeen, Edinburgh, Glasgow, Belfast and Newcastle airports were completely shut.

The Air Traffic Control Service (NATS) imposed restrictions after the Met Office warned that volcanic ash could damage engines. Passengers were being advised to contact their airlines prior to travel.

A NATS spokesman said: "The Volcanic Ash Advisory Center has issued a forecast that the ash cloud from the volcanic eruption in Iceland will track over Europe tonight."

"NATS is working with Eurocontrol and our colleagues in Europe's other air navigation service providers to take the appropriate action to ensure safety in accordance with international aviation policy," he said.

A spokesman of European air control authorities Eurocontrol said in Brussels that the cloud of volcanic ash was expected to reach Belgium airspace at about 16:00 local time (1400 GMT).

To prevent ash particles from damaging aircraft engines, the Eurocontrol grounded flights in Belgium, the Netherlands and northwestern Germany. Due to the intensity of the ash cloud, airspace over northwestern Germany will be closed Thursday afternoon.

Flights would also be halted at Copenhagen Airport, the busiest hub in the Nordic region.

At Copenhagen's international airport, spokesman Henrik Peter Joergensen said some 25,000 passengers there would be affected.

Norwegian Prime Minister Jens Stoltenberg, who is on his way home after a trip to Mexico and the United States, got stuck in New York due to the closure of an airport in Oslo, a spokesperson from his office said Thursday.

Stoltenberg arrived in New York on Wednesday from Washington D.C. to meet a group of entrepreneurs and planned to return to Oslo Thursday, the spokesperson told Xinhua by telephone.

The Oslo Airport Gardermoen was shut down at 10 a.m. local time (0800 GMT) Thursday, airport authorities announced in a statement. It was unknown so far when Norwegian airspace would be reopened.

In Paris, all flights heading north were canceled until midnight.

In Iceland, the ash cloud has not caused problems in the capital of Reykjavik but has affected the southeastern part of the island.

Iceland's second volcano eruption in less than a month began under the Eyjafjallajokull glacier in the south of the country early Wednesday.

Between 700 and 800 people were evacuated from their homes in the area some 120 km east of Reykjavik because of risks of further volcano eruption.