First came a push from the Malaysian premier, then China reached out, but it was only after U.S. President Donald Trump called Thailand's leader last week that Bangkok agreed to talks with Cambodia to end an escalating military conflict.

The fighting between Thailand and Cambodia exposes the depth of global arms proliferation in South-East Asia, proving more sophisticated and deadly than experts expected.

The ceasefire reached in Malaysia was supposed to take effect at midnight on Monday, but it was quickly tested as Thailand and Cambodia continued to accuse each other of violating the truce agreements.