About three blasts, suspected to be resulted from mortar shelling, was heard on Tuesday across the Somali capital where the authorities had imposed a security lock down on the eve of a presidential vote.

No immediate reports of casualties or claims of responsibility were made, although the radical terror al Shabaab group often launches attacks in Mogadishu and says it wants to disrupt Wednesday’s vote to be held behind the airport’s blast walls, Reuters said.

After months of delays, 329 newly sworn-in members of parliament will choose whether to back President Hassan Sheikh Mohamud for a second term or one of 21 rivals.

“All those involved in the election, directly or indirectly, are apostates,” Al Shabaab spokesman Sheikh Ali Mohamud Rage had told Reuters earlier in the day.

Presidential candidates have promised to improve security and the economy. Until now, a construction boom in the bombed out capital has yet to spread far across the rest of the nation.

A severe drought is threatening a new national food crisis. Rival candidates have also accused each other of vote-buying, a practice Western donors have sought to stamp out. Diplomats say corruption continues to hamper development.

Al Shabaab often launches gun and bomb raids in Mogadishu. But it now controls increasingly smaller pockets of territory.

Experts said President Mohamud, who has had to fend off accusations by Western donors of corruption in his government, can rely on the loyalty of about a third of the new lawmakers, giving him an edge but not a guarantee of victory.