The European Commission piled pressure on Switzerland today, saying the country's visa row with Libya risks undermining "the overall coherence" of the border-free Schengen area, dpa reported. The move came a day after Malta announced its intention to defy Switzerland's request to its 24 Schengen partners to keep 188 Libyan officials - including leader Moamer Gaddafi - on a visa black list. A spokesman in Brussels confirmed Home Affairs Commissioner Cecilia Malmstrom called Swiss Justice Minister Eveline Widmer- Schlumpf, urging her "to act rapidly to put an end to this bilateral controversy that risks undermining the overall coherence of the Schengen system." The spat between Libya and Switzerland dates back to 2008 when Gaddafi's son, Hannibal, was arrested in Geneva, allegedly for mistreating his servants. The charges were later dropped but Libya retaliated by arresting two Swiss men on visa charges. The crisis assumed a EU-wide dimension in early 2010. As Switzerland placed Gaddafi and other top officials on the Schengen black list, Libya responded by saying it would stop issuing visas to citizens from all Schengen-area countries. After several failed EU mediation attempts, Malta said Tuesday it would by-pass the row by issuing "Malta-only" visas for Libyan citizens. According to new rules entering into force on April 5, these so- called Limited Territorial Validity (LTV) visas could be extended to Schengen countries that wish to give their consent. Malta has asked Spain, France, Italy and Portugal to join the LTV arrangement, and said it would extend the proposal to others at a meeting Monday in Brussels of the EU's foreign ministers. If all Schengen countries from the EU agree, the Swiss visa ban would become practically worthless, as blacklisted Libyans would be allowed to travel in almost all of Europe. The commission spokesman avoided commenting on the Maltese idea, but said Malmstrom was opposed to "any proposition or initiative (...) that would in effect call into question the very notion of solidarity between the countries that apply the Schengen rules." He also declined to comment on a Libyan request for an official apology from the EU to end the controversy. "I am not aware of any initiative of this kind," he stated. All EU countries bar Britain, Ireland, Cyprus, Bulgaria and Romania take part in the Schengen agreements, plus non-EU members Switzerland, Norway and Iceland.