President Volodymyr Zelenskyy has called Washington’s failure to block the construction of the Nord Stream 2 pipeline to Germany a grave political error, and he is expected to again raise the issue during his talks Wednesday with U.S. President Joe Biden.

Zelenskyy has described the new pipeline as a powerful geopolitical weapon for Russia, which annexed Ukraine’s Crimean Peninsula in 2014 after the ouster of the former Kremlin-friendly president and has thrown its weight behind a separatist insurgency in eastern Ukraine.