Somali authorities on Sunday ended a deadly attack in which at least 20 people were killed and many others wounded when gunmen stormed a hotel in the capital.

It took Somali forces more than 30 hours to contain the fighters who had stormed Mogadishu's Hayat Hotel on Friday evening in an assault that started with loud explosions. The terrorist group al-Shabab, which has ties with al-Qaida, claimed responsibility for the attack, the latest of its frequent attempts to strike places visited by government officials.

The siege ended at around midnight, police commissioner Abdi Hassan Hijar told reporters. "During the attack, the security forces rescued many civilians trapped in the hotel, including women and children," he said. Police are yet to give a detailed explanation of how the attack unfolded. It remains unclear how many gunmen entered the hotel.

Abdulkadir Abdirahman Adan of Aamin Ambulance, a free ambulance service that was part of emergency services and paramedics working to transport wounded to hospitals for treatment, told Anadolu Agency (AA) that despite difficulties regarding security and firefights, they recovered at least seven bodies and 11 wounded people.

The Hayat hotel attack and the siege were the longest by the al-Shabab terrorist group in Somalia and the deadliest upscale attack in Mogadishu since new President Hassan Sheikh Mohamud took office in mid-May.

Abdi Ahmed, among those that were trapped in the hotel, was rescued by security forces during the earlier hours of the attack. He told Anadolu Agency that when the attack began, the hotel was busy, with many businesspeople, traditional elders, government officials and humanitarian workers having coffee.

"It was a nice Friday evening and everyone was happy and having fun but then shattered by double bombing followed by heavy gunfire," Ahmed said. "I was rushed to the cooking room and there was confusion and people running around and everybody trying to hide as the siege unfolded and some hid in bathrooms."

In a statement released by the Foreign Ministry, Turkey condemned the "heinous terrorist attacks in the strongest possible terms" and wished "God's mercy upon those who lost their lives." The country extended "condolences to the relatives as well as to the friendly and brotherly government and people of Somalia," and wished "speedy recovery to the injured."

U.N. Secretary-General Antonio Guterres condemned the attack, according to a spokesperson's statement that said the U.N. supports the people of Somalia "in their fight against terrorism and their march towards peace." Guterres expressed his deep condolences to the families of the victims as well as the government and people of Somalia. He also wished "a swift recovery to the injured."

Somalia's foreign allies joined Turkey and the U.N. in condemning the deadly assault.

The African Union's (AU) transition mission in Somalia (ATMIS) "strongly condemned the attack" and expressed "solidarity with the Federal Government of Somalia to continue with the joint fight against the terrorists and sends heartfelt condolences to the bereaved families."

In a statement released by the State Department, the United States expressed "heartfelt condolences to the families who lost loved ones" and wished "a full recovery to those injured, and commend Somalia's security forces." The statement said, "The United States remains steadfast in our support of Somali and African Union-led efforts to counter terrorism and build a secure and prosperous future for the people of Somalia."

The U.K. and Norway were also quick to express their condemnation of the deadly assault and their support to the government and people of Somalia in the fight against terrorism.