The leaders of Cambodia and Thailand have agreed to meet to negotiate a ceasefire, according to a social media post by United States President Donald Trump on Saturday.

"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.

Bangkok and Phnom Penh have been fighting over territory disputed since colonial power France drew the border between them more than a century ago.

US President Donald Trump on Saturday announced that both the leaders from Thailand and Cambodia have agreed to meet immediately for ceasefire talks after three days of clashes

Of course, trouble at the 508-mile (817 km) shared border is nothing new. For over a century, Thailand and Cambodia have contested sovereignty at various undemarcated points in the thick jungle punctuated with culturally-significant temples albeit with scant strategic or economic value.

The countries continued to trade fire on Friday, and at least 16 people are reported to have been killed.

Its actions will also be a test of its diplomatic strength in the region, they added. Read more at straitstimes.com. Read more at straitstimes.com.

Thailand has rejected mediation efforts from third countries to end the ongoing conflict with Cambodia, insisting that Phnom Penh cease attacks and resolve the situation only through bilateral talks,