China dispatched naval vessels, aircraft and helicopters to the East China Sea on Friday, flexing its muscles in exercises likely to further stoke a bristling territorial dispute with Japan.

A fleet of 11 vessels, including some warships, along with eight aircraft were sent to waters off its east coast, China said, in Beijing’s most confrontational act yet in a row that has chilled ties between the regional heavyweights.

State-run China Central Television showed images of several warships and helicopters carrying out manoeuvres.

It was unclear where in the East China Sea the one-day exercises were taking place. The sea is home to tiny islets known as the Diaoyus in China and the Senkakus in Japan, which are administered by Tokyo but claimed by Beijing.

Tensions in the long-running territorial dispute have soared since the Japanese government’s move last month to formally nationalise the islands, which triggered anti-Japan protests across China and hit the sales of Japanese-manufactured products.

China has since then taken a number of steps seen as snubbing Tokyo, including refusing to send top officials to a global economic conference in Japan this month.

A foreign ministry official in Beijing blamed Tokyo for ratcheting up tension in the region when asked about the exercises at a regular press briefing on Friday.

“The heating up of the dispute over the Diaoyu Islands between China and Japan is entirely caused by Japan’s illegal act of purchasing the islands,” spokesman Hong Lei said.

“The Chinese government’s resolve and determination to safeguard national territorial sovereignty is unswerving.”

Speaking during a visit to Germany, Japanese Foreign Minister Koichiro Gemba said his country was seeking a peaceful resolution to the territorial row.

“What I can say here is that ultimately we are aiming for a peaceful solution based on international law,” he said through an interpreter.

“We must expand the dialogue in Japan-China relations,” he added.

China has previously sent maritime surveillance ships and fisheries patrol vessels to waters near the islands as the row has escalated.

On Tuesday, a Chinese naval flotilla passed near separate islands that are internationally recognised as Japanese.

On Sunday, Japan’s navy marked its 60th anniversary with a major exercise involving about 40 ships in waters south of Tokyo.

The navy’s most modern vessels — including destroyers and conventionally-powered submarines — along with 30 naval aircraft, participated in the event.

China’s exercise on Friday included vessels from the marine surveillance agency and fishery administration, according to the Chinese reports, which did not give a detailed breakdown on the vessels.

“The primary aim (of the exercises) is to strengthen the capacity to safeguard territorial sovereignty and maritime interests,” Shen Hao, a rear admiral in China’s navy said, according to the website of state-run China Radio International.

Microblog users in China broadly welcomed the naval exercises.

“I suggest going to the Diaoyu Islands for some heavily armed exercises — it is our own territory,” said one netizen on Weibo, China’s version of Twitter.

“How exciting,” said another. “This is the emergence of Chinese military power.”

Reports this week said Japan and the United States were considering holding a joint military drill to simulate retaking a remote island from foreign forces.

The exercise, part of broader joint exercises to start in early November, would use an uninhabited island in Okinawa, Japanese media reports said, quoting unidentified sources.