Demonstrators chanted "Free Hong Kong" and sang a protest song as Premier League champions Manchester City hammered Kitchee 6-1 on Wednesday, underlining the political turmoil that has gripped the city.

Bayern Munich target Leroy Sane scored twice, Raheem Sterling got one and set up two more and teenagers Nabil Touaizi and Iker Pozo were also on the scoresheet as Pep Guardiola's City outclassed the Hong Kong league side.

In the 21st minute of each half, marking an attack by a stick-wielding mob on July 21, fans struck up "Do You Hear the People Sing", the Les Miserables song which has been adopted as a protest anthem, followed by loud chants of "Free Hong Kong!"

One banner unfurled among the 20,926-strong Hong Kong Stadium crowd said: "No China extradition, HK = police state, please save HK!!"

It follows weeks of protests in the semi-autonomous territory sparked by a government bid, since shelved, to allow extradition to mainland China for certain offences.

The protests, which have morphed into demonstrations for democratic reform and a halt to sliding freedoms, have seen sporadic clashes including Sunday's attack by suspected triad gangsters which left dozens wounded.

"Sometimes it's a shame this kind of things happen but we were quite well, we moved around Hong Kong and nothing happened and today the game was quite normal," Guardiola said.

"When both sides (protesters and government) are ready and able to find a solution, that is going to happen."

It added a layer of intrigue to what was otherwise a routine win for Manchester City, who conclude their pre-season Asian tour in Japan this weekend before playing Liverpool in the Community Shield a week later.

On a sweltering evening, a sharp-looking Sterling rattled the bar in just the second minute and then set up the first goal for David Villa, who lifted the ball calmly over the Kitchee 'keeper.

Sterling also provided the final pass as Sane, the subject of persistent transfer interest from Bayern Munich, drilled City's second five minutes from half-time.

England striker Sterling made it 3-0 with a neat finish just before the break before Sane grabbed his second with a turn and shot from a tight angle after Kevin De Bruyne's thumping strike.

Spanish teenager Touaizi came on to score City's fifth 10 minutes from time but the biggest cheer of the night was for Kitchee's Law Tsz-chun, who grabbed a consolation goal for the Hong Kong side.

Pozo, another 18-year-old City whizz-kid, poached their sixth goal shortly before another apparent political protest on the 90th minute, when a black-shirted pitch invader ran to the centre circle and exhorted the crowd.

Football has often set the stage for political protest in Hong Kong, where fans routinely boo their own national team's anthem, "March of the Volunteers", which they share with mainland China.