Iraq's national museum officially reopened on Saturday after 12 years of painstaking efforts during which close to a third of 15,000 pieces looted during the US-led invasion were recovered.

The reopening was brought forward in what officials said was a response to the destruction of priceless artifacts by Islamic State group jihadists in the northern city of Mosul.

"We have been preparing to reopen for the past couple of months. The museum should be open to everyone," said Qais Hussein Rashid, deputy tourism and antiquities minister.