Media playback is unsupported on your device Media caption President Sheikh Sharif Ahmed: "We are scared of tomorrow"

World leaders have pledged to boost support for measures to fight piracy, terrorism and political instability in Somalia, after a meeting in London.

The conference agreed a seven-point plan promising more humanitarian aid, support for African Union peacekeepers and better international co-ordination.

US Secretary of State Hillary Clinton said the world must keep Islamist militant group al-Shabab "on the run".

A two-decade war has wrecked Somalia, leaving it without a proper government.

The current transitional government has direct control only in the capital, Mogadishu. It is propped up by 12,000 African Union (AU) peacekeepers.

Al-Shabab militants, who recently joined with al-Qaeda, control large swathes of territory.

Analysis There seems to be a bit of a contradiction in the final communique. On the one hand, it states in bold type that decisions on Somalia's future "rest with the Somali people". On the other it talks about outsiders taking some control of the government's budget, through a Joint Financial Management Board. Doubtless there has been progress today in the fight against al-Shabab and piracy. The delegates made it clear that the time for political transition is over. But Somalia may be entering another phase of violence and instability, this time between its regions, many of which have their own governments. There were no fewer than four Somali presidents at the conference, one representing the transitional federal government, the others the more stable regions in the north. And outside the conference there were no less than three small but noisy demonstrations, all shouting and singing for different causes. This suggests that peace and unity may be still be a distant dream. Will the world help or hinder Somalia? A failed state?

Mrs Clinton ruled out talks with al-Shabab, saying that its decision to join forces with al-Qaeda showed "it is not on the side of peace, stability or the Somali people".

However, she said the international community was ready to engage with anyone willing to renounce violence and embrace the peace process.

Somali officials had earlier urged targeted air strikes against al-Shabab targets, but Mrs Clinton said there was no case for that kind of action.

UK Prime Minister David Cameron, hosting the conference, said setting up an inclusive government was vital to the country's future, and that it must work alongside AU military action.

"Those young people who take up guns for al-Shabab need to be able to see that there is a future in a prosperous stable Somalia that offers them what everyone wants, which is a job and a voice," he told a news conference.

"So the connection between military action to put huge pressure on Shabab, which has been happening, and the political process, they are two sides of the same coin."

In a final communique, the 55 countries and organisations gathered in London said they would:

back the handover of power from the transitional government to an inclusive administration by August

provide more support for African Union peacekeepers

better co-ordinate humanitarian aid, shifting focus to long-term needs

crack down on piracy by expanding on agreements to bring suspects to trial in countries away from Somalia

At the start of the conference, President Sheikh Sharif Ahmed, leader of the transitional government, said Somalis wanted to shake off "horrendous memories of the past", but feared the gathering might be just another diplomatic talking shop.

"Today we are looking for security. We are scared," he said.

"We want to know what happened to the resolutions, all those hopes in the past which never saw the light of day, and which remain as mere words on pieces of paper."

Representatives from many Somali factions attended the London conference, but al-Shabab was not invited.

The militant group denounced the London conference as another attempt to colonise Somalia.

"They want us under trusteeship and we will not allow that. God willing we will face the outcome with full force and stop it," said al-Shabab spokesman Ali Mohamud Rage.

The Islamist militants were forced out of Mogadishu last year, and are under pressure from Kenyan, Ethiopian and Somali government troops elsewhere.

On Wednesday, Ethiopian and Somali troops took control of the strategic stronghold of Baidoa, in the south-west of the country, from al-Shabab.

The BBC's Mohammed Dhore in Mogadishu says security is extremely tight in the city because of the conference, with more than 50 roadblocks compared with the usual five.