London - British Airways (BA) and its alliance partners American Airlines (AA) and Spain's Iberia could be forced to give up valuable take-off and landing slots if they want their transatlantic tie-up to go ahead, the Financial Times reported Monday.

The report said that documents seen by the Financial Times showed that the European Commission argued that the agreement the three airlines signed last year was "likely to result in appreciable competitive harm on seven Europe/US routes."

The routes include lucrative London-New York services. There are also concerns about services between London and Dallas, Boston and Chicago, as well as Madrid to Miami and Chicago.

The planned tie-up between BA, AA and Iberia would deepen the trio's OneWorld alliance by permitting coordinated flight schedules, co-operation on fares and marketing and shared revenues.

The airlines claim that the financial benefits of the new agreement would lead to lower fares, improved scheduling and new transatlantic services. Opponents have voiced fears of a monopoly.

The European Commission concerns are set out in a statement of objections sent three weeks ago to the airlines, which have been given a month to respond, according to the report. The US competition authorities also have to agree.(dpa)