Looking for His glorious appearing! Titus 2:13

Hong Kong's chief executive has warned pro-democracy protesters not to return to the streets for another night of protests after clashes with police temporarily closed the government headquarters.

Chaos erupted as the demonstrators, wearing helmets and wielding umbrellas, charged police after officers warned them to retreat.

Riot police used batons and pepper spray to push them back.

Local media reported that at least 45 people were arrested and police said 11 officers had been injured.

Chief executive Leung Chun-ying told reporters there would be "resolute action" if the demonstrators returned.

"Some people have mistaken the police's tolerance for weakness," he said.

"I call for students who are planning to return to the occupation sites tonight not to do so."

The situation is now said to be calm, although many government offices and shops remained shut mid-morning.

Leaders at the main activists' site in the Admiralty neighbourhood have said they will escalate their campaign after trying to encircle the government headquarters.

Sky's Asia Correspondent Mark Stone said of the clashes: "This is the result of total deadlock between the government and the protesters who want the right to choose their own political leader without interference from China.

"Beijing has said it will allow everyone here to vote but only from candidates chosen by China."

Police had cleared the area more than a month ago during some of the most violent scenes since the demonstrations began in late September.

The democracy movement represents one of the biggest threats for China's Communist Party leadership since its bloody 1989 crackdown on pro-democracy student protests in and around Tiananmen Square in Beijing.

The flare-up comes after four nights of clashes in the working-class district of Mong Kok, across the harbour from Admiralty. 

The Hong Kong rallies drew more than 100,000 on to the streets at their peak, but numbers have since dwindled to a few hundred.

Meanwhile, Prime Minister David Cameron has warned China it was "mistaken" and "counter-productive" to ban a group of British MPs from visiting Hong Kong.

The Commons Foreign Affairs Select Committee had planned to visit the former British colony as part of an inquiry into its relations with the UK, 30 years after the declaration which led to its handover.

But the Chinese embassy said if the group attempted the visit in December then they would be turned away.

Downing Street said that the action had "amplified" concerns about the situation in Hong Kong, and MPs are pressing for an emergency commons debate.

Sir Richard Ottaway, chairman of the Commons Foreign Affairs Committee, said: "The Chinese government are acting in an overtly confrontational manner in refusing us access to do our job."

The joint declaration between China and the UK was signed in 1984 and led to the handover in 1997.