Up to 20 people were killed when Al Shabaab attacked a popular restaurant along Lido beach in Mogadishu late on Thursday.

Most of the dead were civilians - including children - with four of the five assailants being pronounced dead, according to Somali authorities.

The National Intelligence and Security Agency (NISA) had stated that the man leading the assault was in custody.

Though he has not been named, the seized man was said to have been in the list of wanted Al-Shabaab operatives who was also responsible for the attack on Central Hotel in Mogadishu early last year.

Somalia's Minister for National Security Abdirizak Omar Mohamed said Friday that the operation to clear terrorists from Lido Beach had been concluded. The fighting between security personnel and Al Shabaab's assailants lasted about 10 hours.

The country's Deputy Public Prosecutor Mohamed Hassan Nur is said to be among the survivors evacuated from the restaurant by NISA agents during the attack.

Via al-Andalus, a radio owned by Al Shabaab, is said to have announced that the jihadists had attacked the sea food eatery.