Beijing has stepped up its propaganda efforts to show its sovereignty over disputed islands in the East China Sea as tensions between China and Japan linger.
In a rare move, state-run China Central Television broadcast live footage on Thursday of three Chinese maritime surveillance vessels operating in waters around the Diaoyu Islands, known as the Senkakus in Japan.
The three vessels sailed into the waters at around 5am on Thursday and sent warnings in Chinese and English to Japanese patrol boats, asking them to leave.
CCTV reported that the vessels encountered strong winds, but that visibility was the best it had been over the Lunar New Year holiday. A CCTV reporter on one of the vessels, the Haijian 50, said it sailed to within 13 nautical miles of the disputed islands, and similar patrols would be made in the future.
"The Diaoyu Islands are the inherent territory of China," the reporter said.
State media have run high-profile reports of drills by the People's Liberation Army and patrols by the State Oceanic Administration in recent days, stressing that crew members and soldiers had sacrificed their Lunar New Year family reunions to protect the nation's sovereignty.
Tensions between China and Japan have been escalating since September, when the Japanese government announced it was purchasing three of the five uninhabited islands.
In remarks that are likely to heighten tensions, Japanese Defence Minister Itsunori Onodera said on Thursday that Japan had the right to develop the ability to make a pre-emptive strike ahead of an imminent attack given a changing security environment - although it had no plan to do so now.
Onodera made the remarks after North Korea conducted a nuclear test - its third - on Tuesday, but the remarks could upset China and South Korea, which have reacted strongly in the past to such suggestions.
"When an intention to attack Japan is evident, the threat is imminent, and there are no other options, Japan is allowed under the law to carry out strikes against enemy targets," Onodera told Reuters in an interview, adding that Japan still observed peace-oriented diplomacy.
Onodera also called for the setting up of a hotline between China and Japan to prevent any accidental clashes over the disputed islands.
Tensions between the two nations appeared to be easing after a visit to Beijing by Natsuo Yamaguchi, an envoy of Japanese Prime Minister Shinzo Abe who called for a high-level bilateral summit when meeting Communist Party chief Xi Jinping last month.
But tensions flared again last week when Tokyo alleged that Chinese frigates had locked fire-control radar on a Japanese destroyer and military helicopter last month. Beijing denied the claims.