China on Thursday strongly condemned Wednesday's attack in Mosul, Iraq and urged the militants to unconditionally release hostages.

"China is worried about Iraq's worsening security situation. We strongly condemn the terrorist attack against foreign diplomatic agencies and people," said Foreign Ministry spokeswoman Hua Chunying.

Militants from the Islamic State in Iraq and the Levant (ISIL) kidnapped 49 people, including Turkey's consul general, on Wednesday after seizing the Turkish consulate general in Mosul, Iraq's second-largest city, which fell under the group's control a day earlier.

Hua said the relevant side should release the hostages unconditionally and immediately.