Somalia’s government and its foreign backers on Thursday signed a security pact which they presented as a road map towards building a functional national army capable of taking on the fight against al Shabaab militants. The al-Qaeda-affilioated Islamist militant group has lost much of the territory it once controlled in Somalia, including the capital Mogadishu, but its deadly attacks remain one of the main obstacles to stability in the chaotic Horn of Africa country. A London conference on Somalia also heard that the United Nations was increasing its appeal for the country by $900 million to a total of $1.5 billion to allow aid agencies to cope with a severe drought that is causing a humanitarian crisis.