BEIJING,
 Sept 11 (Reuters) - China's vice foreign minister and his Philippine 
counterpart have had a "frank and in-depth" exchange on sea-related 
issues, in particular the issue of the disputed Sabina Shoal, the 
Chinese foreign ministry said on Wednesday.
During
 their meeting, China reiterated its demand for the immediate withdrawal
 of a Philippine vessel and vowed to "firmly uphold its sovereignty", 
the ministry statement showed.
Both countries agreed to continue their dialogue through diplomatic channels.
Xianbin
 Reef, also known as Sabina Shoal, is in disputed waters of the South 
China Sea near the Spratly Islands, which China calls the Nansha 
Islands.
China
 claims sovereignty over most of the South China Sea. The countries have
 clashed over competing claims at several atolls in the sea, through 
which $3 trillion worth of trade passes annually.
Reporting by Beijing newsroom; Editing by Kevin Liffey