The UN envoy for Somalia called Monday for an agreement on holding elections "as soon as possible" after gunfire broke out during an opposition demonstration in the capital Mogadishu last week.

In a quarterly video conference of the UN Security Council, James Swan urged "all of Somalia's political leaders to pull back from confrontation and avoid risky winner-take-all tactics."

"Instead, this is a time to pursue dialogue and compromise to reach an inclusive and credible political agreement to hold elections as soon as possible based on the 17 September model," he added.

Somalia missed a deadline to hold an election by February 8, when President Mohamed Abdullahi Mohamed, better known by his nickname Farmajo, was due to step down, sparking a constitutional crisis in the already-fragile state.

Farmajo and Somalia's five regional leaders reached an agreement on September 17 that abandoned a promised one-person, one-vote ballot but offered a common path forward for elections.

But they have been unable to resolve squabbles over how the vote is to be conducted.

A coalition of opposition candidates have said they no longer recognize Farmajo as president and have vowed mass protests until he steps down.

"I remain convinced that the consensus-based 17 September model offers the best available option to proceed quickly to an electoral process for selection of members of parliament, senators, and the president," the UN envoy said.

"The message from partners has been clear that there should be no partial elections, no parallel processes, and no unilateral actions by Somali leaders. Such approaches would only lead to greater division and risk of confrontation," he warned.

Supporters of different opposition presidential candidates demonstrate in Mogadishu on February 19, 2021
Supporters of different opposition presidential candidates demonstrate in Mogadishu on February 19, 2021 AFP / -

Friday's violence saw a small group of protesters attempt to march down the main airport road when shots rang out, sending them ducking for cover, according to AFP footage of the incident.

It was unclear who opened fire first.

The violence has subsided since, but the months-old political tensions have not eased, said Francisco Madeira, head of the African Union's Somalia mission.

He also called for credible elections to be held as soon as possible.

In Somalia, where the Al-Qaeda-linked Al-Shabaab Islamist militant group remains active, the fragile federal government controls only part of the territory, despite the support of the African Union force, largely funded by the European Union.

The mandate of this force expires on February 28 and is expected to be renewed this weekend by the UN Security Council.

Acting US Ambassador Richard Mills, who also called for elections to be held, said Monday the United States is joining Somalia in calling for some Shabaab leaders to be placed on the UN sanctions list.

"Today we joined with the federal government of Somalia in co-nominating three senior Al-Shabaab leaders, Abukar Ali Adan, Maalim Ayman, and Mahad Karate, to the 751 Somalia sanctions list" he said.

These sanctions include the possibility of asset freezes and travel bans.

"These designations demonstrate that the international community will hold accountable those who undermine Somalia peace, security and stability," the US diplomat said.