BRUSSELS — The European Union warned the British government on Monday not to renege on commitments made ahead of its departure from the bloc earlier this year.

Amid growing signs that trust between the two sides is evaporating ahead of another round of post-Brexit talks in London on Tuesday, the bloc said any attempt by the British government to unilaterally ride roughshod over the divorce agreement could jeopardize the hard-won peace process on the island of Ireland, as well as the prospects for a trade deal.

Ursuala von der Leyen, president of the EU’s executive commission, said she expected Boris Johnson’s government to implement the withdrawal agreement that paved the way for the U.K.’s smooth departure from the bloc on Jan. 31.

She said in a tweet that the agreement was an “obligation under international law” and a “prerequisite for any future partnership.”

She added that the section in the agreement that ensures an open border between Northern Ireland, which is part of the U.K., and EU member Ireland, is “essential to protect peace and stability on the island” as well as for the “integrity” of the EU’s tariff-free and frictionless single market.

Her comments followed a report in the Financial Times newspaper that the British government is planning domestic legislation that would effectively override the international treaty obligations enshrined within the withdrawal agreement.