Nairobi - Kenya's interior minister on Wednesday blocked an attempt to de-register two civil society groups that pointed out anomalies in last week's presidential election, while opposition leader Raila Odinga was expected to announce next steps in disputing what he has called vote-rigging.The National Non-governmental Organizations Board this week said it de-registered the Kenya Human Rights Commission and called for the arrest of the directors of the Africa Centre for Open Governance. Both groups monitored the August 8 vote in which President Uhuru Kenyatta won a second term amid opposition claims of vote-rigging.In a statement, Interior Minister Fred Matiangi said a committee will be formed to look into allegations that the two organizations had tax compliance issues and one was not registered. He also ordered that no action be taken against the groups for 90 days.Meanwhile, activists said Kenya Revenue Authority officials and police raided the offices of the African Centre for Open Governance.Maina Kiai, a former expert for the United Nations on the rights to freedom of assembly and association, said the raid follows claims by the government's NGO board that the group was not registered.Kiai said the group is not registered as non-governmental organization but as a company that falls under a different oversight authority.Tensions remain in Kenya after Odinga rejected the official results of the election. Odinga was expected to make a statement later Wednesday on his party's next moves.Also Wednesday, a top Kenyan electoral official was temporarily stopped from traveling to the United States, officials said.Electoral commissioner Roselyn Akombe was stopped by security agents from boarding a flight to New York late Tuesday, said the officials who insisted on anonymity for fear of reprisals. Akombe, a dual US and Kenyan citizen, was not given any reason why she was stopped from boarding, the officials said.Kenya's electoral commission later said Akombe was delayed at Jomo Kenyatta International Airport by officials who have since apologized. She was to board a flight to the US on Wednesday.