Flight restrictions have been extended in the U.K. and Europe because of the volcanic ash cloud, leaving tour plans and promotional campaigns in tatters.

Several U.K. acts missed the Coachella festival at the weekend, including Gary Numan, the Cribs, Frightened Rabbit and Bad Lieutenant.

All flights in and out of Britain have been stopped because of a volcanic eruption in Iceland. It has also spread across Europe and today airports in Frankfurt, Paris and Amsterdam were closed, while Rome and Madrid airports had a limited service.

Air traffic control service Nats has extended U.K. restrictions to 1am BST on April 20. The shutdown is now in its fifth day.

Now the cloud is affecting U.S. acts heading for, or traveling from, Europe. Miley Cyrus will not be heading to the U.K. and the London premiere of her film "The Last Song" has been canceled. Fellow Hollywood Records artist Selena Gomez - whose single "Naturally" debuted at No. 7 on the new U.K. singles chart - is stranded in Europe.

Usher, whose "OMG" made No. 1 on the new U.K. singles chart, and Adam Lambert are unable to carry out promotional duties in Europe, the BBC reports. U.S. indie-rock band the Features has postponed its U.K. tour until June.

The Irish Aviation Authority (IAA) has extended its ban on flying in Irish airspace until 6pm BST today (April 19). LCD Soundsystem was due to begin its U.K. and Irish tour in Dublin April 20 but the Irish shows have been pulled. The band is still aiming to play their U.K. dates.

Band of Horses is stuck in Europe, as is fellow Columbia act Lissie who was supposed to be filming a video in L.A. Australian band Powderfinger has postponed the U.K. and Irish dates on its farewell tour, due to begin April 20 in Dublin.

Whitney Houston was already in the U.K. for her arena tour. She had to travel by car ferry for her run of dates at the Dublin O2 Arena on April 17, 18 and 20. She then returns to the U.K. for the rest of the month.

U.K. singer songwriter Newton Faulkner is stuck in Hong Kong and unable to reach Europe where his tour was scheduled to continue.

There has also been an impact on the retail sector: all of U.K. entertainment retailer HMV's airport stores are closed, as there are no customers.

The BPI Synch Licensing Mission to Los Angeles has been postponed. It is hoped it will be rescheduled for later in the year. More than 40 U.K. companies were registered to attend the three-day event in Los Angeles and the program included presentations by senior U.S. synch licensing executives and music placement companies, as well as a number of networking events and a formal reception at the U.K. Consulate.

"With the travel situation being so uncertain, there was no choice but to look at postponing the event," said Julian Wall, BPI director of international events, in a statement. "It is with great reluctance that we took this decision and obviously this is a huge disappointment for everybody concerned. I am optimistic that we can reschedule and look forward to announcing another date soon."

One hopeful sign is that volcanic activity decreased dramatically today, U.K. transport minister Lord Adonis told the BBC.

Concert promoter Peter Schwenkow, CEO of DEAG in Berlin, says he has not had any problems in Germany so far. If necessary, he adds, "artists who come from the U.S. will travel to Italy or Spain and then we will drive them to the locations of the concert."

Lufthansa planes started flying again from Frankfurt and Munich to U.S.A. at 4pm CET and all airports are due to open again tomorrow morning. Austria and the Czech Republic have re-opened their airports.

Additional reporting by Wolfgang Spahr in Berlin