Brussels  = The European Union's executive has challenged three of the world's best-known airlines' plans to pool resources on trans-Atlantic flights, saying they might break EU competition rules, officials in Brussels said Friday.

The European Commission sent a formal "statement of objections" to American Airlines, British Airways and Iberia in September, the Brussels-based body said in a statement.

The EU document challenges the three airlines, who are members of the OneWorld alliance, to prove that proposals to share revenues and jointly manage schedules, capacity and pricing on trans-Atlantic routes do not constitute an illegal price-fixing operation.

The move comes almost six months after the commission launched a formal probe into the proposed cooperation deal, saying that it was "far more extensive than the general cooperation between these airlines."

Simultaneously, the commission is also investigating cooperation deals between Lufthansa, Continental, United and Air Canada, and between Air France-KLM and Delta-Northwest. (dpa)