WASHINGTON - President Barack Obama has nominated a career diplomat to be the first US ambassador to Somalia in nearly 25 years, filling a post that has been vacant since the Horn of Africa country collapsed into chaos in 1991, forcing the closure of the American embassy.

Obama on Tuesday tapped Foreign Service veteran Katherine Simonds Dhanani for the job, which will be based in neighboring Kenya until security conditions permit the embassy in the Somali capital of Mogadishu to reopen, the State Department said. Dhanani, currently director of regional and security affairs in the department's Africa bureau, has previously served in India, Mexico, and Guyana and has significant African experience, having been posted in Zimbabwe, Gabon, Zambia, the Democratic Republic of the Congo and the Republic of the Congo.

The State Department said the nomination is a sign of the US commitment to Somalia.

"This historic nomination signals the deepening relationship between the United States and Somalia," spokeswoman Jen Psaki said in a statement. "It also allows us to mark the progress of the Somali people toward emerging from decades of conflict. Somalia has considerable work ahead to complete its transition to a peaceful, democratic, and prosperous nation."

Somalia has been ravaged by conflict and instability since the ouster of dictator Mohamed Siad Barre 24 years ago, despite the formation of successive governments that have been plagued by civil strife, piracy and political uncertainty. The current government continues to battle the al-Qaida affiliated al-Shabab militant group, which has staged attacks around east Africa and earlier this week threatened shopping malls in the United States and other Western nations.

Al-Shabab controlled much of Mogadishu during the years 2007 to 2011, but was pushed out of Somalia's capital and other major cities by African Union forces.

Despite major setbacks in 2014, al-Shabab continues to wage a deadly insurgency against Somalia's government and remains a threat in Somalia and the East African region. The group has carried out many attacks in Somalia and in neighboring countries, including Kenya, whose armies are part of the African Union troops bolstering Somalia's weak U.N.-backed government.

The US Embassy closed in 1991 when Somalia's government collapsed in civil war. The situation quickly deteriorated, prompting the deployment of a US-led U.N. peacekeeping mission. American troops withdrew from Somalia in 1994, months after the humiliating "Black Hawk Down" debacle when Somali militiamen shot down two US helicopters. Eighteen US soldiers were killed in the battle, which marked the beginning of the end of that US military mission to bring stability.