Barack Obama calls Angela Merkel to offer US help after attack: White House

District of Columbia: President Barack Obama has called German Chancellor Angela Merkel to offer assistance and condolences following a deadly attack on a Berlin Christmas market.

"The President offered his condolences, and those of the American people, for the horrific apparent terrorist attack," the White House said following the call late Monday. 

"The President reiterated the US offer of assistance and underscored that no attack could sway our determination -- and that of our German allies -- to defeat terrorism in all of its forms."

Police are still looking for the driver of a truck than ploughed into stalls killing 12 revelers on Monday.

President-elect Donald Trump has gone further than the White House linking the "slaughter" on to an "Islamist terrorist."