Britain has suspended non-essential flights of its Typhoon fighter jets to make safety checks after ash from an Icelandic volcano was found on some planes, the Ministry of Defence said on Thursday.

“It’s a routine safety precaution. We have temporarily suspended non-essential flying,” a ministry spokeswoman said.

The planes had flown on a routine sortie on Wednesday.

The National Air Traffic Service, a British air traffic body, said the decision had not affected civilian flights which have only just resumed after a week of delays caused by the eruption of a volcano in Iceland.

“We’ve made no change to our operations,” NATS spokesman Patrick Horwood said.

“The Ministry of Defence flies in different air space,” he said, without giving further details.

The ministry spokeswoman said some of the Royal Air Force planes were being tested for damage to their engines.

“Initially it was was dust-like deposits, so they looked into it and confirmed it was ash, and now we’re waiting for the outcome of the investigation to see if there was any damage caused,” she said.

Test results are due later on Thursday.

European air traffic agency Eurocontrol said earlier air traffic was likely to be back to normal on Thursday, and that it expected 28,000 to 29,000 flights to operate in Europe.

(Reporting by Mohammed Abbas: Editing by Sonya Hepinstall)