World Bulletin / News Desk

Nigeria's ailing president was glaringly absent on Monday as his deputy marked their two years in power, with no word on the head of state's health three weeks after he went on indefinite medical leave. 

But their election pledges to defeat Boko Haram Islamists and tackle endemic corruption have been overshadowed, first by economic recession and increasingly by speculation about Buhari's health.

The 74-year-old former military ruler spent nearly two months being treated for an undisclosed illness in London in January and February. 

He left for a fresh round of treatment in the British capital on May 7 and has not been heard from or seen since. 

Rumours swirled that he may send a pre-recorded message to the nation for Monday's public holiday. 

But Osinbajo said only in a speech: "I bring you good wishes from President Muhammadu Buhari, who as we all know is away from the country on medical vacation." 

He ended by asking for people's "continued prayers for the restoration to full health and strength and the safe return of our president".