European stock markets drop at open

Europe's main stock markets retreated at the start of trading on Tuesday awaiting region-wide economic data and as traders reacted to news of explosions at Brussels airport.

London's benchmark FTSE 100 index dropped 0.6 percent to 6,149.35 points compared with Monday's close.

In the eurozone, Frankfurt's DAX 30 shed 1.1 percent to 9,836.28 points and the Paris CAC 40 lost 0.7 percent to 4,396.87.

Mike van Dulken, head of research at Accendo Markets, said that the "explosion at Brussels airport... has knocked sentiment".

Brussels airport is closed until further notice, Eurocontrol, the European organisation for air navigation safety confirmed on its website Tuesday following twin explosions.

Two blast were heard at the airport shortly after 8:00am (0700 GMT) Tuesday, Belgian media reported. Belgian police said at least one person had been killed and several wounded.