German Chancellor Angela Merkel rebuffed U.S. pressure last month to conduct a naval maneuver in Russia’s backyard aimed at provoking President Vladimir Putin, according to three people familiar with the talks, Bloomberg reported.

At a Feb. 16 meeting at the Munich Security Conference, U.S. Vice President Mike Pence urged Merkel to send German ships through a narrow channel between the Crimean peninsula and mainland Russia to show Putin that Western powers won’t surrender their access to those waters, according to the officials, who spoke on condition of anonymity.

The German leader declined, they said, citing reservations from Ukrainian President Petro Poroshenko. A spokesman for the chancellor declined to comment.