Politicians loyal to President Sheikh Sharif Ahmed quickly said Sharmarke’s departure would put an end to the internal divisions that have beset the Transitional Federal Government (TFG) and slowed government business to a crawl.

Ahmed said he welcomed Sharmarke’s decision to quit and said he would nominate a new prime minister as soon as possible. It was not immediately clear who would be candidates for the post.

Some Horn of Africa analysts, however, said the change of leadership would be seen as a propaganda coup by Islamists and change little as long as the divisions of power between the president and prime minister were poorly defined.

“This is an attempt by Ahmed and his allies to re-invent the TFG but this cannot be achieved by changing an individual, said Rashid Abdi, a Nairobi-based Somalia analyst at the International Crisis Group.

“It is a problem with the hybrid system (of governance) which ... is supposed to bring checks and balances but Somalia’s culture of a strong leader lags behind that system.”

Abdi said the beleaguered Ahmed, a former Islamist rebel, was looking for a scapegoat as he tried to reassert his authority over a brittle administration and disillusioned nation.

The Sufi militia group Ahlu Sunna Walijamaca, which earlier this year signed a power-sharing deal with the TFG, warned Sharmarke’s departure would only worsen the insecurity.

Flanked by Ahmed, the outgoing Sharmarke said he was stepping down in the light of the crisis within government and escalating violence in Somalia.

Last week, Ahmed criticized Sharmarke for failing to resolve the conflict and said numerous Cabinet reshuffles had yielded no improvements.

“This could be a good opportunity for the transitional government. It could generate new political capital if the new PM is competent and gains the support of the Somali people,” said Afyare Elmi, a Somali professor of politics based in Dohar.

Whether the leadership shuffle steadies the interim administration, whose mandate is expected to expire in August 2011, will depend on who replaces Sharmarke, a diplomatic source said.

The Al-Qaeda-linked Al-Shabaab militants have stepped up their offensive to topple the government in the last six weeks. A suicide bomber blew himself up outside the presidential palace compound on Monday night, wounding two peacekeepers.