Oil prices slipped on Monday as the U.S. did not exert more pressure on Russia to end the Ukraine war by implementing further measures to disrupt Russian oil exports after the presidents from both countries met on Friday.

Brent was below $66 a barrel after closing 1.5% lower in the previous session, while West Texas Intermediate was near $63.

Oil prices could swing wildly depending on how the summit goes. Any movement toward a peace deal on Russia’s war in Ukraine could lead to crude benchmarks dropping below $60 a barrel, some analysts say. If the talks end with the U.S. imposing stricter sanctions, prices could top $80 a barrel.