British Airways, American Airlines and Iberia have offered changes to plans to share more of their lucrative trans-Atlantic routes in an effort to settle an antitrust dispute with the European Union, EU regulators said Monday.

The European Commission said "it is assessing the effectiveness of proposed commitments" put forward by the three airlines to soothe EU worries that expanding their oneworld alliance may violate rules that forbid companies striking deals that shut out rivals.

It said it would ask rival airlines to examine the changes and would keep probing the deal until it could make a decision on whether to accept the proposal. It gave no details of what the airlines have offered to do.

If BA, American and Iberia manage to reach a settlement with EU regulators, they would avoid cartel fines that can go as high as 10 percent of global annual revenue.

In the U.S., the Department of Justice said in December that the tie-up would cause competitive harm and hike prices unless the airlines surrendered some take-off and landing slots. A final decision must be made by the Department of Transportation.

The three airlines currently coordinate how they sell and operate flights between the 27-nation EU and the United States. They now want to expand the alliance to jointly manage schedules, capacity and pricing on flights from Canada, Mexico, Puerto Rico, Norway and Switzerland as well.