Media playback is unsupported on your device Media caption John Sudworth looks at why China has chosen now to parade its military might on an unprecedented scale

China has held a lavish parade in Beijing to mark the defeat of Japan in World War Two, showcasing its military might on an unprecedented scale.

President Xi Jinping in his opening speech paid tribute to "the Chinese people who unwaveringly fought hard and defeated aggression" from Japan.

He also said the People's Liberation Army would be cut by 300,000 personnel, a move expected to be finished by 2017.

China's growing military power is being keenly watched amid regional tensions.

China has several territorial disputes with neighbours in the South China Sea, as well as with Japan in the East China Sea.

Ahead of the parade, the US said five Chinese ships had been spotted in the Bering Sea off Alaska for the first time.

China's People's Liberation Army (PLA) is the world's largest military, with 2.3 million members. China also has the second biggest defence budget after the US.

Image copyright Reuters

More than 30 foreign government officials and heads of state including Russia's President Vladimir Putin and UN Secretary General Ban Ki-moon attended the event.

But many Western leaders and Japan's Prime Minister Shinzo Abe have stayed away.

Some 12,000 troops and 200 aircraft, as well as tanks and missiles, were on display in Tiananmen Square, including the anti-ship "carrier killer" missile Dongfeng-21D.

Most of the war machinery on display was being shown to the general public for the first time, according to state media.

Mr Xi, also the commander of the armed forces, was centre stage at the parade's proceedings.

Media playback is unsupported on your device Media caption A look at the new weapons systems on display at China's WW2 parade

Image copyright Reuters Image caption Mr Xi inspected the troops after his speech

Image copyright Reuters Image caption Military helicopters formed the number 70 to mark the 70th anniversary of the end of World War Two in Asia

Image copyright EPA Image caption Shore-to-ship missiles were on display in the parade

John Sudworth, BBC News, Beijing: "We are strong now"

Despite the repeated assurances from China that the message of today was one of peace, the crowd seemed to see a different symbolism in the V-shaped lines of jets and bombers.

"We have the ability to announce to the world that we are a big country, we are a great country," one onlooker told me. "It is the proper time to show to the world that we are strong now," a young woman agreed.

China believes that its suffering and sacrifice during World War Two have been largely forgotten.

But 70 years on there are questions over whether the Communist Party is basking in reflected glory - after all it was the Nationalists who did most of the fighting and dying - and whether a contribution to world peace is really best marked by such an extraordinary display of military might.

'China will not seek expansion'

Mr Xi made the troop reduction announcement in a speech where he reassured the global community that "China will remain committed to peaceful development".

"No matter how strong it becomes, China will never seek hegemony or expansion. It will never inflict its past suffering on any nation," he said.

BBC China Editor Carrie Gracie, who was at the parade, says the army cuts will not mean a weaker China.

It is also upgrading its naval and air forces, she says, so does not need as many boots on the ground to project its power around the world.

Alexander Neill from the International Institute for Strategic Studies (IISS) in Singapore, says the move shows China's "determination to have a modern fighting force".

Image copyright Reuters Image caption Some 12,000 military personnel and 200 aircraft took part in the huge display in Beijing

Image copyright Reuters Image caption South Korea's Park Geun-hye, Russia's Vladimir Putin, and former President Jiang Zemin are among the dignitaries attending

Image copyright EPA Image caption People's Liberation Army war veterans took part in the parade

Image copyright Reuters Image caption Military aircraft performed fly-bys with colourful trails to symbolise China's bright future, television commentators said

Image copyright Reuters Image caption A large area around Tiananmen Square was blocked off for the parade, and Beijing residents gathered at the perimeter to watch

In the build-up to the event, state media have published commentaries reinforcing Chinese patriotism and views on historical events.

Entertainment shows were also suspended on television to make way for the coverage.

Beijing's normally smoggy skies were unusually blue, after factories were closed, barbecues banned and cars stopped from travelling to reduce pollution.

But concerns about China's growing military assertiveness and the tone of the parade meant many Western and Asian leaders stayed away from the event.

"During a period of strained relations between China and Japan, as well as increasing military tension in the Asia-Pacific region, some leaders are reluctant to be associated with what they may view as a nationalistic, anti-Japanese mass rally," says Mr Neill.

Japan launched a full-scale invasion of China in 1937 and, according to Beijing, eight years of fighting claimed 14 million Chinese lives.

China also claims that it is the "forgotten ally" and that its role in defeating Japan has been underplayed in the post-war narrative.

Nationalist forces led the fight against Japan in China. They were defeated by Mao Zedong's Communists who proclaimed a people's republic in 1949.