BEIJING - Chinese President Xi Jinping on Tuesday extended condolences to his German counterpart Joachim Gauck over Monday's fatal attack on a Christmas market in Berlin.

Xi said in his message that he was shocked to learn a truck smashed into a Christmas market Monday in Berlin causing heavy casualties.

Xi, on behalf of the Chinese government and people, mourned the dead and extended his heartfelt sympathy to the bereaved families and those injured.

"China firmly opposes terrorism in all forms, supports Germany in its efforts to maintain safety and stability and is willing to strengthen anti-terrorism cooperation with the international community including Germany to jointly safeguard world security and prosperity," said the Chinese president.

Twelve people were killed and nearly 50 others injured when a truck drove into a popular Christmas market filled with tourists and locals in Berlin late Monday.