TOKYO May 28 (Reuters) - Japan said on Wednesday it was unable to immediately provide decomissioned patrol ships to Vietnam amid heightened tensions in the South China Sea as its own coastguard was stretched by surveillance activities.
As tensions mount between China and other claimants to the South China Sea, countries such as Vietnam and the Philippines are rushing to bolster their maritime patrols.
Japan, itself locked in a bitter territorial spat with China, in March agreed to dispatch a research team to Vietnam as a step toward providing it with patrol ships.
Asked about the possibility of providing used patrol ships to Vietnam to expedite the process, Prime Minister Shinzo Abe told parliament: "Surveillance duties are getting heavier for the Japan Coast Guard."
"Regrettably, our country is not in a situation where we can retire all the vessels that have reached such age."
Patrol ships from China and Japan have been playing cat and mouse in waters near disputed East China Sea islets, raising fears of an accidental clash between the world's second- and third-largest economies.
In the South China Sea, scores of Vietnamese and Chinese ships, including coastguard vessels, have continued to square off around a Chinese oil rig in contested waters.
Vietnam said earlier this week a Chinese boat rammed and sank a Vietnamese fishing vessel not far from the oil rig, while China's official Xinhua news agency reported the vessel capsized after "harassing and colliding with" a Chinese fishing boat.
In an interview with Reuters last week, Vietnamese Deputy Prime Minister Vu Duc Dam said Hanoi was keen to have aid from Japan and other countries to help manage its coastline and waters. (Reporting by Kiyoshi Takenaka; Editing by Jeremy Laurence)