U.N. Secretary-General Ban Ki-moon is urging Somali leaders to “seize the moment” and finally restore stability and hope to the troubled east African nation.

During a historic visit to the capital, Mogadishu, on Friday, Mr. Ban warned Somalia has “a very limited window of opportunity” to turn around its state of affairs.

He stressed Somalia must follow a roadmap toward new elections and reform its parliament and constitution. The U.N. leader said Somalia must hold on to military gains this year against the al-Qaida-linked militant group, al-Shabab.

Mr. Ban also announced the U.N. will move its Somalia office from Kenya to Mogadishu in January.

He encouraged the Somali government to continue working with the international community to deliver humanitarian aid to drought and famine-stricken areas.

The visit marked the first trip to Somalia by a U.N. secretary-general since 1993, two years after the country's last stable government collapsed.

The visit came just as Mogadishu has experienced a surge in violence. Since late November, there have been 15 bomb attacks in Mogadishu. The government has blamed them on al-Shabab.

In an interview with VOA on Thursday, a former official with Somalia's National Security Agency said al-Shabab appears to have adopted guerilla tactics to destabilize Mogadishu.

Colonel Abdulahi Ali Maow also said al-Shabab has apparently created a unit of more sophisticated fighters, some of whom may have infiltrated pro-government forces.

Al-Shabab has been fighting AU and Somali government forces in an effort to impose strict Islamic law in Somalia.