Muammar Gaddafi has reportedly been blacklisted by Switzerland
The European Commission has condemned Libya's decision to stop issuing visas to the many Europeans whose countries are in the Schengen border-free zone.
The commission says it "deplores the unilateral and disproportionate" Libyan decision and the nations affected will consider an "appropriate reaction".
Libya's move came after Switzerland allegedly blacklisted 188 high-ranking Libyans, denying them entry permits.
The Swiss ban is said to include Libyan leader Muammar Gaddafi and his family.
Switzerland is in the 25-nation Schengen zone - European countries that have abolished mutual border controls.
Reports say Libya's visa ban is already in force at Tripoli's main airport.
The Times of Malta reports Libya has refused entry to eight Maltese citizens. It says one of them, an accountant with 25 years of business experience in Libya, had to spend about 20 hours in a room before catching a flight back to Malta.
"They treated us like hostages, not even allowing us out of the room to stretch our legs," the passenger was quoted as saying.
The Libyan-Swiss row dates back to July 2008, when Col Gaddafi's son Hannibal and daughter-in-law were arrested in Switzerland. The charges, of mistreating two domestic employees, were later dropped.
Libya then halted oil exports to Switzerland, withdrew billions of dollars of assets from Swiss banks and put two Swiss businessmen working in Libya on trial for visa violations and other offences.
Italy and Austria - Schengen members - are among the countries that have invested heavily in Libya's oil sector and construction projects.
The Schengen zone includes 22 of the 27 European Union member states. Switzerland is not in the EU but is in Schengen, as are two other non-EU countries - Iceland and Norway.
The five EU member states not in Schengen are: Bulgaria, Cyprus, the Irish Republic, Romania and the UK.