Japan has begun construction work on a military radar station near the disputed Senkaku islands.
The move will anger China as it may allow Japan to expand surveillance near the Chinese mainland.
According to the BBC, the new base, on Yonaguni island, is located just 150km from the Senkaku island.
About 150 personnel are due to be deployed on Yonaguni within two years.
During a ceremony to mark the start of project, Japanese Defence Minister Itsunori Onodera suggested his country's military presence could be extended to other islands in the region, the report added.