NAIROBI, Dec 28 (Reuters) - The United States has said the attempted suspension of Somalian Prime Minister Mohammed Hussein Roble was alarming and that it supported his efforts for rapid and credible elections. The U.S. State Department African Affairs Bureau said in a tweet late on Monday that it was also prepared to act against those obstructing Somalia"s path to peace. On Monday, President Mohamed Abdullahi Mohamed said he had suspended Roble"s powers for suspected corruption, a move the prime minister described as a coup attempt, escalating a power struggle between the two leaders. read more