BRUSSELS, Feb 5 (Reuters) - The European Commission is considering ways to force foreign airlines to hike what it reckons are unfair cut-price fares, giving a new armoury against U.S. and other competitors, an official said on Tuesday. "We are thinking about giving the EU tools to fight against any future unfair pricing on air traffic," Commission spokesman Gilles Gantelet told Reuters. He said any new European Union system could be modelled on duties imposed on shipping firms judged by the Commission to be undercutting minimum prices on trips to and from EU ports. Maritime anti-dumping rules have been in place since 1986. The Commission reckons that the EU needs clearer rules since aviation pricing falls outside World Trade Organisation (WTO) regulations. The United States and the EU are the world's biggest aviation markets. Gantelet denied that the measures were a response to aid from Washington to keep airlines in business after a global downturn for the sector since the September 11 suicide hijacker attacks. "What we're thinking about is not against a specific country," Gantelet said. "It's just that we are lacking such a tool." He said the plans had not had not yet been fully drafted and declined to predict when they might be adopted. U.S. AID PACKAGE Even so, the Commission has expressed concern in the past that a $15 billion U.S. package of aid last year may skew competition, especially on lucrative transatlantic routes. Washington says that the aid, comprising $5.0 billion in cash to compensate for the shutdown of U.S. airspace after the September 11 attacks and $10 billion in loan guarantees, does not amount to any subsidies. The possible penalties would be imposed on airlines in nations with which the EU has no bilateral agreements. In Europe, these include Switzerland and some nations in central and eastern Europe. Gantelet defended aid handed out over the years to EU airlines, saying it was done under strict conditions. "Any state aid given to European airlines, included that companies receiving aid could not have price leadership on the most price sensitive routes," he said. Under the possible rules, the Commission would investigate allegations by EU carriers of unfair pricing on flights to and from EU destinations by foreign airlines. If it agreed, it could slap penalties on the foreign airline. Loyola de Palacio, the Commissioner in charge of transport, also said at the weekend that the Commission was considering measures to penalise third country airlines. "It is time to rethink the international agreements and to work for a better international liberalisation of the sector," she said in a speech at the World Economic Forum in New York.