The US has threatened to impose sanctions over Somalis who attempt to thwart the UN-supervised political process aimed to bring peace to the country. US Assistant Secretary of State for African Affairs Johnnie Carson made the remarks after making the first visit by a top US official in two decades. He said his trip to Mogadishu was to acknowledge \"significant progress\" made against al-Shabab militants. The US would impose sanctions on anyone standing in the way of the political process now under way, Carson indicated. \"The kind of action we must take against spoilers range from visa sanctions to travel sanctions to asset freezes,\" he added. The US would consider stationing officials in the capital permanently \"when we believe that it is both appropriate and safe\", he remarked. The UN roadmap includes forming a new parliament and constitution for the country before August 20.