Ireland reimposed a ban on flights in and out of Dublin and other airports on Wednesday due to a cloud of volcanic ash drifting south from Iceland, the Irish Aviation Authority said.
The IAA, which stopped flights in most of Ireland for several hours on Tuesday, said it would halt all Dublin flights from 1000 GMT due to risk of ash ingestion in aircraft engines.
Restrictions were also ordered on airports in Donegal, Sligo and Knock, from 0700 GMT, said a statement on the IAA's website. No restrictions will apply to Shannon airport or Galway airport until further notice, it said.
British regulators ordered an airspace shutdown over parts of Scotland and Northern Ireland from 7:00 am (0600 GMT) for 12 hours for most affected airports, warning that high ash levels could damage plane engines.
After a cloud from the Iceland volcano last month caused the biggest aerial shutdown in Europe since World War II, ash once again grounded flights in British airspace late Monday.