MOGADISHU, Somalia (AP):

Somalia's president resigned yesterday after a four-year term in which his Western-backed government failed to extend its power throughout a country crippled by infighting and a strengthening Islamic insurgency.

Abdullahi Yusuf's resignation, which comes amid deepening international pressure, could usher in more chaos as Islamic militants scramble for power - even though the government controls only pockets of the capital, Mogadishu, and the seat of parliament in Baidoa.

Within hours of the announcement, mortar shells slammed into the streets near the presidential palace in Mogadishu, where the government maintains a token presence.

Somalia has been beset by two decades of anarchy, violence and an insurgency that has killed thousands of civilians and sent hundreds of thousands fleeing for their lives.

"Most of the country is not in our hands," Yusuf said in a speech before parliament in Baidoa, referring to Islamic insurgents with alleged ties to al-Qaida.

When Yusuf took office in October 2004, the country had been divided into fiefdoms ruled by rival warlords since 1991, when a socialist dictator was overthrown.

There were more than a dozen previous peace efforts and two previous governments, but they never managed to take effective control over the country. Yusuf's government has never been strong.

Islamic insurgents

The last time Yusuf lost his grip on the nation to Islamic insurgents, in 2006, he made the unpopular decision to call in troops from neighbouring Ethiopia to prop up his administration. The call backfired - Somalis saw the Ethiopians as "occupiers" and accused them of brutality.

The insurgents used the Ethiopian presence as a rallying cry to gain recruits even as the Islamists' strict form of Islam terrified many Somalis into submission.

In many ways, Yusuf is leaving Somalia much as he found it.

But this time, insurgents are in control of most of the country, prompting fears it could become a haven for terrorists.