Oil prices extended gains on Wednesday after the US shot down an Iranian drone and armed Iranian boats approached a US-flagged vessel in the Strait of Hormuz, rekindling fears of an escalation in tensions between Washington and Tehran. Brent crude futures were up 56 cents, or 0.8%, at $67.89 per barrel at 0400 GMT. US West Texas Intermediate crude was up 63 cents, or 1.0%, at $63.84 per barr