European stock markets down as Hong Kong protests force airport closure

European stock markets dropped Monday as escalating protests in Hong Kong forced the closure of the financial hub's airport.

London, Frankfurt and Paris all slid into negative territory approaching the half-way stage, having rallied at the open, as news of the shutdown spread.

"Reports that authorities have closed the airport in Hong Kong sent markets lower after what had been a positive open in Europe," said Neil Wilson, chief analyst at traders Markets.com.

"Hong Kong has kind of been under the radar of most traders... but increasingly I feel like that this has the potential to spiral into a bigger market worry. Today's moves highlight the risks," he added.

All flights in and out of Hong Kong were cancelled late Monday after thousands of pro-democracy protesters flooded into the city's airport to denounce police violence.

The abrupt shutdown came as the Chinese government signalled its rising anger at the protesters, denouncing some of the violent demonstrations as "terrorism".

Hong