BRUSSELS - European Union (EU) leaders on Thursday agreed to speed up efforts to strengthen the bloc's single market, with enhanced cooperation among at least nine member states possible if progress stalls, European Council President Antonio Costa and European Commission President Ursula von der Leyen said.

Speaking after an informal retreat of EU leaders in Brussels, Costa said there was broad consensus on advancing toward "one market for one Europe," underlining the urgency of the process and calling for concrete steps in 2026 and 2027.

"We all agree with the importance of moving forward quickly this year," he said. "To make sure our companies can operate seamlessly across our 27 member states with a simple and single set of corporate rules."

Von der Leyen said she would present a "One Europe, One Market Roadmap and Action Plan" in March, outlining specific measures and a timetable for implementation.

She emphasized that a fully functioning single market requires a deep and liquid capital market. "Here we agreed that we want to be done with phase one of the Savings and Investment Union, which includes the market integration, the supervision and the securitization, by June," she said.

If progress among all member states proves difficult, enhanced cooperation remains an option, von der Leyen added.

"At least nine member states, if they want, can move forward faster and decide to be more ambitious," she said, noting that if not all 27 countries are ready to advance at the same pace, a smaller group could proceed under the enhanced cooperation mechanism.

EU leaders also discussed the importance of keeping trade open and agreed to prioritize diversification efforts to protect their shared interests.