Oil prices extended gains on Monday, with Brent headed for a record monthly rise, after Yemeni Houthis launched their first attacks on Israel over the weekend, widening the US-Israel war with Iran in the Middle East. Brent crude futures jumped $3.09, or 2.74%, to $115.66 a barrel by 2353 GMT after settling 4.2% higher on Friday. US West Texas Intermediate was at $102.56 a barrel, up $2.92