BRUSSELS - Brussels, Belgium-headquartered NATO has started the last part of its moving to the new headquarters in the same city, the bloc said Monday.

Standing opposite to the site of the old headquarters, the new premises set to house NATO boasts more than 254,000 meter square of space, and has been designed to resemble interlocking fingers, symbolizing the unity and cooperation, the NATO said in a statement.

Over the next 12 weeks, around 4,000 NATO civilian and military staff, as well as 29 national delegations, will transfer to their new offices.

NATO Secretary General Jens Stoltenberg said, "We are moving to a cutting-edge and environmentally-friendly building which makes a fitting home for the Alliance in the 21st century."

According to the statement, NATO has been in its old, temporary headquarters since 1967. The old building is overcrowded and requires constant and costly maintenance.

The new headquarters is a "green building" which is expected to be 30 percent more energy efficient.

Construction of the new headquarters building began with a ground-breaking ceremony in December 2010, and the official handover from host country Belgium to NATO took place in May 2017.