At least four flights, including two that departed from UK airports, were affected by bomb threats on Tuesday, in a series of incidents that caused unplanned landings and forced a Polish airport to close temporarily.

Warsaw-Modlin Airport was shut for a time on Tuesday after a passenger plane operated by Polish airline LOT, which was flying from London Heathrow, was diverted there. The aircraft had originally been due to land at Warsaw-Chopin Airport before the threat forced the unscheduled landing.

Warsaw-Modlin reopened around midday after the security alert was stood down, with officials confirming that no device had been found on board the aircraft.

A bomb threat was also reported on an SAS flight travelling from Copenhagen to Warsaw. That aircraft landed at Warsaw-Chopin Airport, and the airport later confirmed that no device was found after checks were carried out on the plane.

In another incident, a Ryanair plane flying from Manchester was forced to make an emergency landing at Murcia airport in southern Spain because of a further threat. A total of 114 passengers and seven crew members left the plane after it touched down.

Francisco Lucas, the Spanish government's delegate in the region, said on X that the Civil Guard had ruled out the presence of explosives on the plane from Manchester following its inspection. He added that the airport had resumed normal activity.

Also on Tuesday, a plane flying from Israel landed at Sofia airport in Bulgaria after a bomb threat was received by email. It was the fourth flight caught up in the day's wave of alerts.

The alerts came a day after a Wizz Air flight from London to the Bulgarian capital Sofia was diverted to Budapest airport on Monday following another bomb threat. Hungarian defence minister Romulusz Ruszin-Szendi announced the diversion in a Facebook post.

The flights affected were a Ryanair service from Manchester to Murcia, a LOT flight from London Heathrow to Warsaw, an SAS flight from Copenhagen to Warsaw, and the flight from Israel which landed at Sofia. In each of the cases where inspections were completed, officials said no explosives were found.