Mortar shells struck residential neighbourhoods near the presidential palace in Somalia's capital Mogadishu on Sunday shortly after parliament convened to approve the recently appointed cabinet, underlining the security challenges confronting the new government.

In addition to a looming famine, the Horn of Africa nation also faces a grinding Islamist insurgency, with Al-Shabaab militants ratcheting up their attacks in recent months.

On Sunday, as parliament met to approve Prime Minister Hamza Abdi Barre's 75-member cabinet, which includes a former Al-Shabaab deputy leader, several rounds of mortar shells landed near the presidential palace, according to a security official and a witness.

"We have no recorded casualties so far as investigations are ongoing," district security official Mohamed Abdifatah said.

One of the rounds damaged a medical facility in the area, according to an onlooker.

"One of the mortar rounds struck in the midst of the Xararyaale intersection and another hit a hospital close by," Abdikadir Yare, a witness, said.

There was no immediate claim of responsibility for the attack, which came weeks after recently elected President Hassan Sheikh Mohamud hinted at his government's willingness to negotiate with Al-Shabaab, saying it would only happen when the time was right.

A total of 229 legislators voted in favour of the new cabinet, with seven votes against and one abstention.

Former Al-Shabaab deputy leader and spokesman Muktar Robow, who once had a $5-million US bounty on his head, will be the new religion minister.

Robow, 53, publicly defected from the Al-Qaeda-linked militants in August 2017.

The US embassy in Mogadishu on Sunday congratulated Mohamud and Barre "on the confirmation of their selections for the new cabinet".

"The United States is eager to continue our engagement in support of #Somalia's revival," the embassy said on Twitter.

Soon after Mohamud's election in May, US President Joe Biden ordered the re-establishment of a US troop presence in Somalia to help in the fight against Al-Shabaab, reversing a decision by his predecessor Donald Trump to withdraw most US forces.

Al-Shabaab has waged a bloody insurrection against the Mogadishu government for 15 years and remains a potent force despite an African Union operation against the group.

Its fighters were ousted from the capital in 2011, but continue to wage attacks on military, government and civilian targets.

In July, Mohamud said ending the violent insurgency required more than a military approach.