Al-Shabab militants attacked an African Union peacekeeping base in the Somali capital Thursday, the Associated Press reported. A spokesman for the group claimed responsibility for the attack. The group reportedly targeted a Christmas party at the base.

The sounds of gunfire and explosions were heard coming from the African Union Mission in Somalia (AMISOM) base, next to Mogadishu's international airport. The base also houses United Nations offices. According to Reuters, the airport area and base are outfitted with tight security cordons and blast walls. Several embassies are also in the area. Roads leading to the airport were sealed off following news of the attack.

"Our fighters have entered AU's Halane base by force through the gate and now fighting is going on inside the base," al-Shabab military spokesman Abdulaziz Abu Musab said. Musab also said several African Union soldiers had been killed.

AMISOM spokesman Col. Ali Aden Houmed told the AP at least eight men stormed the base. Three were shot and killed by AU forces while two detonated themselves near a fuel depot. Three are believed to have escaped.

Houmed said African Union soldiers may also have been killed in the attack though he gave no further information.

Nicholas Kay, the United Nations special representative to Somalia, condemned the attack on Twitter, saying terrorists "will not stop Somalia [from] rising.” The official Twitter account for AMISOM posted an update Thursday saying the base “is safe and under control.”

There are more than 20,000 African Union troops in Somalia to help the country battle al-Shabab, an insurgent organization linked to al Qaeda. Al-Shabab has been carrying out suicide and gunfire attacks throughout Mogadishu since 2011 when it was pushed out by AU forces.

Earlier this month, an al-Shabab car bomb killed at least four people in a U.N. convoy in Mogadishu.