Iceland's most active volcano, Grimsvotn, began erupting on Saturday, causing airlines to cancel over 1,000 flights in northern Europe on Tuesday and Wednesday due to fears over aviation safety.

Ash cloud warnings over Britain and Ireland were lifted on Wednesday but in Germany, Bremen and Hamburg airports were briefly closed while Berlin is also expected to be disrupted. European air traffic control agency Eurocontrol said on its Twitter page that eruption was coming to an end.

The Grimsvotn volcano is only blowing out steam and concerns over the impact on aviation from ash contamination are easing, weather and aviation officials told Reuters.

We expect the volcanic-ash clouds that have grounded hundreds of European flights to disappear during the day, allowing airlines to resume normal services, meteorologists told Wall Street Journal.

Ash clouds caused by the eruption of Grimsvötn volcano cleared the United Kingdom, Ireland and Scandinavia on Wednesday, but areas of ash concentration over parts of northern Germany caused disruption.

Unsafe ash levels required the closure of some airspace and Hamburg and Bremen airports, which handle 480 and 120 daily flights, respectively, German aviation regulators told Wall Street Journal.

Take a glimpse of Hamburg airport, which was forced to close after volcanic ash from Iceland: