US President Joe Biden on Monday warned that if Russia invades Ukraine, there would be no Nord Stream 2, but did not specify how he would go about ensuring the controversial pipeline would not be used.

Speaking at a joint news conference with German Chancellor Olaf Scholz, Biden said, “If Russia invades… again, then there will be longer Nord Stream 2. We will bring an end to it.”

When asked how he would do that, he responded, “I promise you we will be able to do it.”

Europe’s most divisive energy project, Nord Stream 2 is designed by Russian energy giant Gazprom to double the amount of gas flowing from Russia straight to Germany, bypassing traditional transit nation Ukraine.

The United States and Germany have sought to present a united front against potential Russian military aggression in Ukraine, with Biden declaring the two in “lockstep” despite questions over Berlin’s commitment to scuttle the important energy pipeline.