A senior U.S. State Department official is threatening sanctions against any Somalis who work against the peace process in Somalia.

Assistant Secretary of State for African Affairs, Johnnie Carson, said after a day-long visit to Somalia Sunday that the United States will take action against those he calls “spoilers” who impede efforts to draw up a new constitution and elect a new president.

Carson said the sanctions would include a travel ban and an asset freeze and would apply to those in the government as well those outside of it.

Somalia is facing an August 20 deadline to implement a roadmap for a new government. The country has been without a stable central government since 1991.

Carson is the highest-ranking U.S. official to visit Somalia in 20 years. He held talks with the heads of the transitional government — President Sheikh Sharif Sheikh Ahmed and Prime Minister Abdiweli Mohamed Ali.

President Ahmed said the high-level visit shows that Somalia's security situation is improving and ties with the U.S. are strengthening.

Somali and African Union peacekeeping forces have had success against al-Shabab — militants who have been fighting to turn Somalia into a conservative Islamic state.

The United States is offering $33 million for information on the whereabouts of seven al-Shabab leaders. The State Department says the group is responsible for the killing of thousands of Somali civilians, peace activists, international aid workers, journalists, and AU peacekeepers. It says al-Shabab threatens the stability of East Africa and the national security interests of the United States.

Al-Shabab once controlled much of Somalia and nearly all of the capital, Mogadishu. But it has lost most of its territory during an 18-month offensive involving African Union forces, the Somali government, Ethiopia and Kenya.