U.S. oil prices climbed on Monday to finish at their highest level of the month so far, buoyed by ongoing concerns about tight supplies with no end in sight for Russia’s war in Ukraine and a reported production outage at Libya’s largest oil field.

West Texas Intermediate crude for May delivery rose $1.26, or 1.2%, to settle at $108.21 a barrel on the New York Mercantile Exchange. That was the highest front-month finish since March 25, FactSet data show.

NYMEX ULSD rose $.036 to $3.8908 with MYMEX gas going down $.0033 to $3.3781

Natural-gas futures, meanwhile, climbed by more than 7%. “Unseasonably cold temperatures are driving elevated spring heating demand in the U.S. amid an already bullish fundamental backdrop of subdued inventory levels and no real signs of rising production in the near to medium term,” said Tyler Richey, co-editor at Sevens Report Research.

May natural gas added 52 cents, or 7.1%, to settle at $7.82 per million British thermal units — the highest finish since September 2008.