Cologne, Germany  - Nine people were missing Tuesday after historical archives and two neighbouring buildings collapsed in the west German city of Cologne.

A spokesman for the city fire brigade said that a search of the rubble was underway to try to find the missing people with officials saying it was unclear how many injured there are likely to be.

"The complete area was shrouded in a dark mist, just like September 11," said Paraskevi Oustampasiadi, whose newspaper stand is near the collapsed buildings.

Speculation about the cause of the collapse is focused on new building work for the city's underground transit system, which runs directly below the archives.

The archives hold documents which charter Cologne's development over its 2,000-year history. (dpa)