Long-festering tensions over border territory have escalated into armed conflict between Cambodia and Thailand, leading to dozens of deaths on both sides and displacing tens of thousands of people.

The tank screeches as it rolls into the ad-hoc military base before four battle-weary soldiers jump out to re-inspect the hefty vehicle.

SURIN, Thailand (AP) — Thailand and Cambodia traded accusations Saturday of fresh attacks as deadly border clashes entered a third day, leaving at least 33 people dead and more than 168,000 displaced, as international pressure mounted on both sides to reach a ceasefire.

"The U.S. already flunked the test and that should be a wakeup call," a former senior U.S. State Department official told Newsweek.

Thailand and Cambodia exchanged heavy artillery fire for a second day on Friday as border fighting intensified and spread, while Cambodia's leader said Thailand had agreed to a Malaysian ceasefire proposal but then backed down.