President Barack Obama will cut short a visit to Ireland and leave Monday evening as a plume of ash from a volcano in Iceland heads toward the British Isles, threatening to strand him on the ground.

Obama’s entourage,including Air Force One and a chartered plane carrying the White House press corps, had been scheduled to fly from Dublin, Ireland, to London on Tuesday morning. But the plume of ash from the Grimsvotn volcano in Iceland was expected to cover Ireland, Scotland and parts of northern Britain by 6 am Tuesday, according to reports in London.

British authorities said late Monday that airspace would be closed at 7 am Tuesday, local time, over Northern Ireland and Scotland. News reports in London said airlines already were grounding flights.

The earlier departure for London will not change Obama's planned state visit to London Tuesday, accordingto Deputy White House Press Secretary Josh Earnest.

Last year, an ash cloud from another Iceland volcano wreaked havoc on European air travel for days. It also forced Obama to cancel a trip to Poland to attend the funeral of its president; a trip he’s making up this week after stops in Ireland, the United Kingdom and France.