When European Union (EU) finance ministers wrapped up their three-day gathering?in Madrid?on Sunday, they found it difficult to make their way home.

Thousands of flights have been canceled across Europe after the ash cloud from a volcanic eruption in Iceland hovered over the continent and threatened the safety of planes. Airports in 24 European countries have been closed so far.

This left EU finance ministers who did show up for the gathering with no other choice but to take overnight trains or even coaches back home.

Spain's Finance Minister Elena Salgado, who chaired the meeting as representative of the EU's rotating presidency, said EU Economic and Monetary Affairs Commissioner Olli Rehn had to skip the final press conference so as to rush back to Brussels by taking a train at first to Paris.

The German delegation, headed by deputy finance minister Joerg Asmussen, also ended its participation ahead of schedule owing to the "unusual circumstances surrounding the return trip." Both Germany and France canceled planned press conference on Thursday.

In addition to those early leavers, the three-day meeting was plagued by absences. At least a quarter of the 27 EU finance ministers, including those from Belgium, Britain, Finland and Denmark, failed to arrive in Madrid after their home flights were canceled.

The EU finance ministers were supposed to have a session with their Asian counterparts on Saturday and Sunday. Unfortunately, they found so few people to talk to.

Finance ministers from 16 Asian countries as well as Russia and Australia had been invited to join the session, but only four of them managed to attend. Six other countries had to send junior officials as substitutes. Six Asian countries, including China and Japan, had no people at the table at all due to cancellation of flights.

The chaos at the EU finance ministers' meeting was just part of the disruption of the EU's workings due to the volcanic ash cloud. EU agriculture ministers had planned to meet on Monday in Brussels, but the meeting has been canceled.

It was not yet clear whether a four-day plenary session of the European Parliament, scheduled to start on Monday in Strasbourg, France, would be called off.

In response to the air travel crisis, EU transport ministers were due to hold a video conference on Monday to decide whether to reopen air spaces as airlines urged an immediate re-think of flight restrictions.

Millions of air passengers have been left stranded across Europe. The alternatives such as trains and buses were rapidly filled up.

The volcanic ash has caused huge loss of revenues to the airline industry.

European Commission President Jose Manuel Barroso has decided to set up an ad-hoc group to assess the impact of the volcanic ash cloud on the air travel industry and the economy.

"The volcanic ash cloud has created an unprecedented situation," Barroso said in a statement, adding that it is important that all measures to be considered are coordinated at the European level.