Oil prices edged up on Monday after fighting between Russia and Ukraine intensified over the weekend, although concerns about fuel demand in China, the world's second-largest consumer, and forecasts of a global oil surplus weighed on markets.

Brent crude futures gained 29 cents, or 0.4%, to $71.33 a barrel by 0502 GMT, while U.S. West Texas Intermediate crude futures were at $67.20 a barrel, up 18 cents, or 0.3%.

Russia unleashed its largest air strike on Ukraine in almost three months on Sunday, causing severe damage to Ukraine's power system.

In a significant reversal of Washington's policy in the Ukraine-Russia conflict, President Joe Biden's administration has allowed Ukraine to use U.S.-made weapons to strike deep into Russia, two U.S. officials and a source familiar with the decision said on Sunday.

There was no immediate response from the Kremlin, which has warned that it would see a move to loosen the limits on Ukraine's use of U.S. weapons as a major escalation.

Source: Reuters