The de facto US embassy in Taiwan has released a photo showing US and Taiwanese coast guard vessels sailing together, a rare move intended to reassure Taipei amid increased Chinese pressure.

Taiwan detected a sharp increase in Chinese ships operating in waters around the island last month, according to a Taiwanese coast guard official, as Beijing intensifies its pressure on Taipei.

A Taiwanese Coast Guard vessel engaged in a two-day 'face-to-face confrontation' with a Chinese Coast Guard ship near the disputed Pratas Islands in the northern South China Sea over a territorial dispute.