They also threatened penalties against those who hamper political progress.
In a communique scheduled to be issued after the one-day summit, the group of 55 nations and international organisations said Somalia “remains precarious and in urgent need of support from the international community”.
Delegates at the talks, hosted by British prime minister David Cameron in London, included Somalia’s UN-backed transitional government, US secretary of state Hillary Clinton and UN secretary general Ban Ki-moon.
Somalia has had transitional administrations for the past seven years, but has not had a functioning central government since 1991, when warlords overthrew a longtime dictator and turned on each other, plunging the nation into chaos.
Clinton said the mandate of Somalia’s transitional government must end in August as planned, and warned that travel bans and asset freezes could be imposed against those who attempted to hamper progress.
“There must be no further extensions,” the summit conclusions said.
Leaders hailed tentative signs of progress in Somalia, which has seen piracy attacks decline and the al Qaida-linked militant group al Shabaab largely driven out of the capital Mogadishu.
Despite differences expressed over the role of al Shabaab in Somalia’s future, the conclusions call for “all those willing to reject violence to join” the country’s UN-led peace process.
Nations also agreed “to ‘develop a defectors’ programme to support those who leave armed groups” and pledged to help improve efforts to tackle terrorism and increase work to stop extremists travelling to and from Somalia.
Cameron said other nations were still wary that al Shabaab could export terrorism to Europe and the US, with dozens of British and American citizens travelling to Somalia to train and fight.
“If the rest of us just sit back and look on, we will pay a price for doing so,” he told the conference.
In their communique, leaders said the use of private armed guards aboard ships off Somalia’s coast had helped disrupt pirate attacks — which saw the shipping industry pay out $135m (€101m) in ransoms last year. Pirates currently hold seven vessels and 191 hostages, compared to 32 ships and 661 hostages in Jan 2011.
Leaders said there “will be no impunity for piracy,” and demanded more effort to prosecute those responsible in both Somalia and neighbouring countries.