Sudans ruling military acknowledged that security forces committed violations when they moved in to disperse protesters at a sit-in camp outside military headquarters in Khartoum last week as the United States demanded a probe in the violence. The spokesman for the ruling military council, Gen. Shams Eddin Kabashi, told reporters at a news conference late Thursday that an investigation was underway and that several military officers were already in custody for alleged "deviation" from the action plan set by military leaders. "We feel sorry for what happened," said Kabashi. "We will show no leniency and we will hold accountable anyone, regardless of their rank, if proven to have committed violations." Over 100 people were killed in the capital and across Sudan in a sweeping crackdown on June 3, according to protest organizers. Protesters also said more than 40 bodies were pulled from the Nile River in Khartoum and taken away by security forces. US assistant secretary of state for Africa Tibor Nagy on Friday called for an "independent and credible" investigation into the crackdown. "The USA believe very strongly there has to be an investigation which is independent and credible which will hold accountable those committing the egregious events," he said from Addis Ababa after a two-day visit to Khartoum. "The events of June 3rd constituted, in our point of view, a 180-degree turn in the way events were going, with murder, rape, by members of the security forces," he said in a conference call with journalists. "Until June 3rd, everybody was so optimistic. Events were moving forward in such a favorable direction after 35 years of tragedy for Sudan". Amnesty International also called for an international probe. "Following this admission, it is now more urgent than ever, in the interest of accountability and transparency, that the military authorities allow international scrutiny and investigations by the UN and African Union into the escalating human rights violations under their watch," said Sarah Jackson, Amnestys deputy regional director for East Africa, the Horn and the Great Lakes. The dispersal of the sit-in was a violent turn in the standoff between the protesters and the military, which removed President Omar al-Bashir from power in April after a months-long popular uprising against his 30-year rule. Kabashi admitted that the members of the transitional military council had convened the night before the sit-in was dispersed and agreed to drive protesters away. Forces for the Declaration of Freedom and Change, a coalition of political groups representing the protesters, also insisted on an international investigation — a demand Kabashi strongly rejected. On Thursday, UN Special Representative of the Secretary-General on Sexual Violence in Conflict Pramila Patten expressed "grave concern" over reports of mass rapes of protesters and female medical personnel by security forces and militias. Human Rights Watch urged the Sudanese military to restore access to the internet, which has been blocked since the start of the clampdown. Kabashi ruled that out, alleging the use of social media has posed a threat to national security. Sudanese protesters have relied heavily on social media to post video depicting violence perpetrated by security forces, mobilize rallies and coordinate dissent.