Haiti's National Library was looted Wednesday by armed gangs terrorizing the Caribbean nation's capital Port-au-Prince, its director told AFP, as UNESCO condemned multiple "devastating" attacks on educational and artistic institutions in the city.

Library director Dangelo Neard said the history of Haiti -- the Western Hemisphere's second-oldest republic -- was being threatened.

"Our documentary collections are in danger. We have rare documents over 200 years old, with importance to our heritage, which risk being burned or damaged by bandits," he said.

"I was told that the thugs are taking away the institution's furniture. They also ransacked the building's generator."

Armed groups control most of Port-au-Prince and swaths of countryside in the absence of a functioning government and continued delays in establishing a promised transitional authority.

After several days of relative calm, attacks picked up again in several neighborhoods of Port-au-Prince from Monday.

The attack on the National Library comes after assaults last week on two universities, the Ecole Normale Superieure and the National School of Arts.

The National School of Arts "promotes the development of artists and the influence of Haitian art throughout the world," UNESCO, the UN's education, science and cultural organization, said in a statement condemning vandalism at the institution.

The Ecole Normale Superieure, meanwhile, which UNESCO said was the site of an arson, is "one of the pillars" of the country's education system, as well as the oldest training institution for teachers in the country.

"These acts of vandalism, looting and arson against the country's educational institutions have devastating consequences for the future of Haitian society," UNESCO said.

Also last week, two health care facilities and 10 pharmacies were looted, the UN's humanitarian office said Wednesday, while the remaining hospitals are facing increasing strain.

The country's embattled national police said in a statement Tuesday that they were "determined and committed to restoring order and peace."