TOKYO, April 17 (Reuters) - Crude oil futures fell slightly in quiet trading on Monday, after a three-day Easter break, as investors digested a third consecutive weekly gain in prices along with North Korea's failed missile launch on Sunday.
Benchmark Brent crude futures LCOc1 were down 18 cents 55.71 at 0047 GMT. On Thursday, before the break closed most major markets, they settled up 3 cents at $55.89 a barrel.
U.S. West Texas Intermediate crude futures CLc1 were also down 18 cents at $53. They rose 7 cents to $53.18 a barrel on Thursday.
Both benchmarks closed out the Easter holiday eve higher for a third consecutive week, with Brent adding 1.2 percent over the four days and WTI up 1.8 percent.
The subdued start to this week came as markets braced for more geopolitical tensions over North Korea, after its attempted launch on Sunday of a ballistic missile failed as the projectile blew up almost immediately. United States is working with allies and China on responses to the failed test, U.S. President Donald Trump's national security adviser said on Sunday.
Crude traders and investors in Asia also had their first chance to assess a 13th consecutive increase in the rig count by drillers of U.S. shale oil.
Energy services firm Baker Hughes said on Thursday that drillers added 11 oil rigs in the week to April 13, bringing the total count up to 683. RIG/U