Unknown assailants attacked and withdrew inside a United Nations police base in the Malian city of Timbuktu on Friday morning, the United Nations said, with the morning assault coming on the heels of recent attacks on foreign entities in Mali and West Africa.

The attackers drove up to the entrance of the UN base in the former Hotel Palmeraie at around 6:30am local time and then blew up their vehicle, according to Olivier Salgado, a spokesman for the UN peacekeeping mission in Mali (MINUSMA). A checkpoint in the city operated by Mali's army also came under fire.

"An unknown number of assailants have withdrawn inside the camp. An operation is currently under way with Malian and MINUSMA forces," he said, adding that an injured police officer had been evacuated.

There were no city residents staying at the base, which lies near the entrance of Timbuktu, and a Nigerian police contingent had reportedly been in charge of the site, a military source told Reuters. Salgado said the site was empty at the time of the attack, except for a few guards on duty.

The Malian army checkpoint was attacked by gunman simultaneously at the same time in the city's Kabara neighborhood, located near the airport. It was not immediately clear if there were any casualties.

No one has claimed responsibility for Friday's attack, but Islamist militants, who briefly held the city of Timbuktu in 2012 until French forces drove them out, have stepped up activities in Mali in recent months as part of a growing regional insurgency. Last month, al Qaeda fighters seized a Swiss missionary living there and set conditions for her release.

On a Friday morning in November, gunmen stormed into the Radisson Blu hotel in the capital Bamako and opened fire, kicking off a bloody siege that lasted for nine hours. The assailants kept the 170 staff and guests under siege in the hotel, typically considered a safe haven for foreign visitors. They killed 19 people, with six Russians, three Chinese, an American, a Belgian, a Senegalese, an Israeli, and at least six Malians among the victims.

Mokhtar Belmokhtar group Al Mourabitoun claimed responsibility for the attack, saying on Twitter that it carried out the attack "with the participation" of al Qaeda in the Islamic Maghreb (AQIM). Malian jihadist group Macina Liberation Front (MLF) issued a dueling claim of responsibility. In August, MLF and Al-Mourabitoun made similar dueling claims to a deadly hotel siege in the central Malian town of Sévaré.

Al Mourabitoun, which recently pledged allegiance to al Qaeda in the Islamic Maghreb (AQIM), claimed responsibility for an attack in January on a hotel in Burkina Faso's capital Ouagadougou. The group took more than 170 hostages, killing 30 and injuring another 50 people at the four-star Splendid hotel. While this was the first militant attack in the capital city, the Islamist group said last May that it was holding a Romanian man who had been kidnapped from a mine in northern Burkina Faso the previous month.