MOGADISHU, Somalia (AP) — Al-Qaida-linked militants detonated multiple bomb blasts and breached the main U.N. compound in Mogadishu on Wednesday, sparking gun battles with security forces that killed at least 12 people. U.N. personnel who reached the compound's secure bunker all survived, though officials hinted not all reached that bunker. An ambulance driver said that five Somali civilians were killed and an Associated Press reporter who went inside the U.N. compound after the battle saw two dead bodies of what appeared to be al-Shabab attackers wearing Somali military uniforms. An official said seven attackers died in total. Ben Parker, a spokesman for the United Nations Assistance Mission in Somalia, said that a first explosion was detonated at 11:30 a.m. and that at least two others followed. Dozens of staff from U.N. humanitarian and development agencies were in the compound and many moved to a secure bunker, he said. African Union and Somali security forces responded and took control of the compound about an hour later. The U.N. staff who sought refuge in the bunker were then evacuated to the secure military base and airport complex across the street, Parker said. "There is a provision there for a secure area within that compound and that wasn't breached," Parker said. Parker was then asked if that meant all U.N. people survived: "Assuming that people got to the safe area," he said. "There was not very much time to get into the safe area." A second U.N. official who could not be named because he is not an official spokesman indicated an announcement of U.N. casualties was upcoming. A third U.N. official said he believed four U.N. workers were killed, including one Kenyan, one Somali and two South Africans. The official said seven attackers died. Several U.N. guards were believed to have also been wounded, or worse. Both U.N. officials insisted on anonymity because they are not official spokesmen. Mohamed Ali, an ambulance driver, said he transported five dead civilian bodies and 10 people who were wounded. Somali Prime Minister Abdi Farah Shirdon said he was appalled that "our friends and partners" at the U.N. who are carrying out humanitarian activities would be the victims "of such barbaric violence." An African Union official, Mahamet Saleh Annadif, condemned the "cowardly" attack and sent condolences "to those who had lost loved ones." The U.N. has had only a small presence in Mogadishu in recent years, due to the dangers of operating in a city controlled by al-Shabab militants. In December, though, U.N. Secretary-General Ban Ki-moon touched down in Mogadishu wearing a bullet proof jacket to announce a return of the U.N.'s political office to the seaside capital. That security measure was necessary because of al-Shabab, the al-Qaida-linked militant group. Al-Shabab said on its Twitter feed shortly after Wednesday's attack that its fighters "are now in control of the entire compound and the battle is still ongoing." Al-Shabab said that members of its martyrdom brigade were carrying out the attack. An AP reporter at the scene said one of the three blasts included a car bomb that largely pulled off the compound's front gate. Bullet marks could be seen on the inside walls. The compound under attack lies just across the street from the secure airport complex, where African Union military forces are based. The U.N. compound is used by agencies like UNICEF, WHO and UNDP. The top U.N. official on Somalia, Nicholas Kay, also works out of the building. He was not inside the compound when it was attacked and was safe inside the airport compound. Mogadishu fell into anarchy in 1991 and is just beginning to move past years of sustained conflict. The U.N. and foreign embassies were absent from Mogadishu for close to two decades. But African Union forces pushed al-Shabab out of Mogadishu in August 2011, meaning residents didn't have to live through daily battles for the first time in years. An international presence slowly began to return and the U.N. began the process of moving its personnel from the nearby capital of Nairobi, Kenya, back to Mogadishu, a process that has accelerated in recent weeks. International embassies — from Turkey and Britain, for example — followed. Wednesday's attack, though, underscores the fragile security situation and will force the U.N. and embassies to review their safety plans and decide if they have enough defenses to withstand a sustained al-Shabab assault. Fadumo Hussein, a shopkeeper who was sitting inside her shop near the attack said she barely escaped unharmed. "It started with an earsplitting explosion, followed by heavy gunfire," she said, showing holes made by bullets on her shop. "I crouched and then crawled like an animal, I am very lucky. It was a shocking moment."