20100121

ABUJA (Reuters) - Nigeria's ailing president, in hospital overseas for the past two months, faced mounting pressure on Thursday to end a power vacuum that is increasingly worrying investors.

Critics want President Umaru Yar'adua to formally hand over executive powers to his deputy or quickly return to ease uncertainty in sub-Saharan Africa's second-biggest economy.

Thousands marched in Lagos to protest Yar'Adua's absence, while the Nigerian Bar Association urged a federal court in Abuja to intervene in the political crisis.

Yar'Adua has not been seen publicly since leaving Nigeria on November 23 to be treated for a heart ailment in Saudi Arabia.

The 58-year-old leader has refused to formally transfer power over to Vice President Goodluck Jonathan, prompting a federal court last week to rule that Jonathan can exercise executive powers but cannot be "acting president."

The uncertainty has slowed government business, threatens a fragile peace in the oil-producing Niger Delta and raises concern about the legality of decisions made while Yar'Adua is in hospital.

"In the president's absence, and realistically until a new president is elected in 2011, the outlook will deteriorate for foreign investors and security will decline in terms of regulatory risk and political violence," said Elizabeth Stephen, an analyst with London-based insurance broker Jardine Lloyd Thompson.

Despite the constitutional risks, some investors are hoping the vice president will take charge so that reforms, especially in oil and the banking sectors, can get back on track.