LONDON, Aug 12 - Ukraine and a group of its largest creditors are holding make-or-break talks that look highly unlikely to deliver an amicable deal to restructure $19 billion of debt, Reuters reported.

The often bitter negotiations have dragged on for five months, snared on whether the bonds' face value should be written down. Kiev says it will halt debt payments if an agreement is not reached this week.

Without a last-minute compromise, that appears to be the likeliest outcome of the meeting in San Francisco, putting Ukraine on course for a "hard" default. It must pay a $60 million coupon on Aug. 23 and a chunkier $500 million bond maturing on Sept. 23.