NAIROBI, KENYA

International donors pledged more than $350 million to Somalia’s fledgling government Tuesday, a cash infusion they hope wil help scale back the Islamist extremism that has radiated from Somalia across the region. 

The money was promised at a meeting co-hosted byBritain’s prime minister, David Cameron, and Somalia’s president, Hassan Sheikh Mohamud, at what they called a “pivotal moment” for the war-torn nation. 

Islamist insurgents allied to Al Qaeda have been pushed out of major cities, there have been no successful pirate attacks for close to a year, and Somalia’s diaspora is returning to open businesses,according to a communique released at the end of the conference. 

“The people and government of Somalia can rightly be proud of the huge progress the country has made over the past year,” said Britain’s Foreign Secretary William Hague in a statement.

More than 50 countries and organizations attended Tuesday’s gathering in London. 

“A new parliament and government have been appointed in the most representative political process in a generation. Al Shabab has lost large areas of territory,” Mr. Hague said. “The diaspora are returning and the economy is starting to revive. But this progress is fragile, and maintaining the momentum will require leadership in Somalia and support from the region and the international community.” 

Washington said it would give $40 million to add to the $1.5 billion it has spent in Somalia since 2009, making it the country’s largest bilateral donor. Britain promised $279 million and theEuropean Union $58 million. (To learn more about US-Somalia relations, read about the rocky path to American diplomatic recognition of the Somali government.)

Most of the money has been earmarked for security sector reform, which includes paying for international trainers to teach new recruits to the Somali police force expected double in size to 12,000 officers. 

A new radio communications network is planned along the length of Somalia’s coastline, the longest in Africa, to help the fight against piracy. 

The national army would also be strengthened, to give it the muscle needed to extend the areas it controls, which are still limited to the capital Mogadishu and territory nearby. 

Al Shabab, which on Sunday exploded a car bomb in that city, killing eight people, is still a major threat and has promised more guerrilla-style attacks. 

The fight against radical Islam must be maintained because it is a threat to regional and international stability, Mr. Cameron said at the end of the summit. 
“New terrorist threats have emerged in parts of Africa,” he said. “Radicalism is poisoning young Somali minds and breeding terrorism and extremism. This is a threat to our security, and if we ignore it, we will be making the same mistakes in Somalia that we made in Afghanistan in the 1990s.” 

Mr. Mohamud, who was inaugurated as president in September at the end of an eight-year UN-backed transitional administration, said the support was “very, very encouraging.”

“We have been given a chance and we will prove in the eyes of the world that we will deliver,” he said. “We cannot afford to miss this golden opportunity and we hope the world’s support and commitment will be materialized soon.”