The U.S. government Thursday urged all sides in Ethiopia's post-election violence to return to calm after clashes between police and unarmed protesters left at least 26 dead this week, dpa reported, "The violence is unacceptable, the threat of violence is unacceptable," White House spokesman Scott McClellan said. "All parties need to exercise restraint and maintain an atmosphere of calm." The spokesman for U.S. President George W. Bush said disputes about Ethiopia's election should be handled by the electoral commission and the legal process. Meanwhile, Ethiopian security forces must show restraint and act in accordance with international human rights standards, McClellan told reporters. He said Bush discussed Ethiopia's strife with U.N. Secretary- General Kofi Annan in a telephone call Thursday. The United States has also been in touch with Ethiopian goverbnment officials and opposition leaders, McClellan said. -- SPA 2306 Local Time 2006 GMT