Somali legislators gathered behind the blast walls of the capital's airport yesterday to elect their president, after months of delays and threats from Islamist insurgents bent on derailing the process.

The protracted vote began with 14000 elders and prominent regional figures choosing 275 members of parliament and 54 senators, who in turn now choose whether to back President Hassan Sheikh Mohamud for a second term or one of 21 rivals.

The presidential vote, originally slated for August, is likely to take several rounds before a winner is declared.

Mohamud, who has led the country since 2012 as it tries to rebuild after more than two decades of war and chaos, has the support of about a third of legislators, experts say, giving him an edge but not a guarantee of victory.

The threat from Islamist al-Shabaab rebels, who regularly launch attacks in Mogadishu and elsewhere, meant the government and its Western backers scrapped a plan to give each adult a vote due to the challenge of securing polling stations.

Al-Shabaab, which had ruled Somalia for several years, has been slowly driven out of its major strongholds.

But its fighters launch regular gun and bomb attacks in their bid to topple the government and impose their strict interpretation of Islam.