At least four passenger flights across Europe were targeted by suspected bomb threats on Tuesday, prompting emergency landings and security checks in Poland, Spain and Bulgaria. All four aircraft landed safely, with counter-terrorism units and police deployed to inspect them. The incidents came a day after a separate bomb threat forced a Wizz Air flight from London to Sofia to divert to Budapest.In Poland, two separate flights were affected. A LOT Polish Airlines Boeing 737 MAX flying from London Heathrow to Warsaw Chopin Airport was diverted to Warsaw-Modlin after a bomb alert was received at 9.54 am local time. The aircraft landed at 10.01 am with 181 people on board, including a group of Jewish students aged 16 and 17 travelling from London on a school delegation. Passengers were evacuated and the aircraft moved to an isolated area for inspection. Modlin Airport was temporarily closed before resuming operations.A Scandinavian Airlines (SAS) flight from Copenhagen to Warsaw also faced a bomb threat. The aircraft landed normally at Warsaw Chopin Airport and passengers disembarked, the airline said. Police took charge of the investigation, while airport operations continued.In Spain, a Ryanair flight from Manchester made an emergency landing at Murcia airport following another reported threat. The aircraft was carrying 121 people, including crew, according to Francisco Lucas, the Spanish government’s delegate in the Murcia region.In Bulgaria, a flight from Israel landed at Sofia airport after a bomb threat was received by email, Reuters reported, citing local media. Counter-terrorism units were deployed to check for possible explosive devices. The airport’s website showed an El Al service from Tel Aviv as the only flight arriving from Israel that morning. Bulgarian public broadcaster BNT said the alert was part of a wider warning affecting “various institutions”.The latest incidents follow a bomb threat on Monday involving a Wizz Air flight from London Luton to Sofia. The aircraft was diverted to Budapest and escorted by a Hungarian Gripen fighter jet. Wizz Air later said security checks had been completed and nothing suspicious was found.Several similar alerts involving flights to and from Israel were reported last month. An Austrian Airlines flight from Tel Aviv to Vienna was diverted to Sofia on October 18, while two Delta Air Lines flights faced separate bomb warnings earlier in the month. No explosives were found in those incidents, according to Ynet.Authorities have not established whether Tuesday’s threats were connected. Each alert was being treated as a security matter, with aircraft inspected and passengers evacuated or screened where required.