The Obama administration has formally acknowledged U.S. drone strikes killed four Americans in Yemen and Pakistan. In a letter to Congress, Attorney General Eric Holder confirmed the United States deliberately killed the militant cleric Anwar al-Awlaki in Yemen in 2011. Holder also acknowledged the deaths of Awlaki’s 16-year-old son, Abdulrahman, and the elder Awlaki’s aide, Samir Khan, in Yemen, as well as the death of Jude Kenan Mohammad in Pakistan. But Holder suggested those strikes were accidental, saying all three “were not specifically targeted.” Mohammad’s killing had previously been unknown, and as of Wednesday he was still on the FBI’s Most Wanted list.

Attorney General Eric Holder’s letter was revealed on the eve of today’s major counterterrorism address from President Obama. The president is expected to announce a policy limiting targeted killing outside of war zones, in places such as Pakistan, Yemen and Somalia. He is also expected to endorse using the same standards for attacking foreign suspects now used for American citizens. The move could end the so-called signature strikes that treat foreign males in a target zone as militants unless they are proven innocent after death. We’ll have more on Obama’s targeted killing program after headlines with “Dirty Wars” author Jeremy Scahill.

President Obama will also use his speech today to outline new efforts to close the U.S. military prison at Guantánamo Bay. Obama is reportedly preparing to gradually lift his more than three-year ban on repatriating Yemeni prisoners. The Yemeni transfers will likely begin at a slow pace of around two or three prisoners at a time. More than half Guantánamo Bay’s 166 prisoners have been cleared for release, including 56 from Yemen. More than 100 are currently on a hunger strike at Guantánamo to protest their indefinite imprisonment. In a letter to the Pentagon, a group of lawyers for Guantánamo prisoners pleaded for improved conditions at the prison, writing: “While the hunger strike continues to increase in scope and severity, there is much you can do, right now, to improve the quality of life for all the prisoners.”

The damage from this week’s devastating tornado in Moore, Oklahoma, could top $2 billion. Oklahoma City Mayor Mick Cornett told reporters the storm may have damaged up to 13,000 homes.

Oklahoma City Mayor Mick Cornett: “The numbers of this event are becoming even more staggering: 33,000 people affected, 12,000 to 13,000 homes impacted, property damage is $1.5 to $2 billion. Obviously, this is a significant event, and it’s one that’s going to take us a while to address.”

The death toll from the tornado stands at 24 after initial estimates of 91 dead were revised. Six people remain unaccounted for. President Obama is scheduled to visit Oklahoma on Sunday.

The FBI says the man it shot dead in Florida on Wednesday implicated himself and Boston Marathon suspect Tamerlan Tsarnaev in a 2011 triple murder. Agents were questioning Ibragim Todashev at his Orlando apartment when he allegedly tried to attack them. Initial reports said Todashev had lunged at the agents with a knife, but law enforcement officials later said the details are unclear. The FBI is claiming Todashev had just admitted that he and Tsarnaev were involved in killing three men in Massachusetts to prevent their potential testimony over a botched drug deal.

A British soldier was hacked to death in London on Wednesday in what is being described as a likely terrorist attack. A bystander videotaped one of the two suspects just moments after the killing, holding a cleaver in his bloodied hands. Speaking to the camera, the man delivered a political message signaling ties to Islamist militancy.

Suspect: “We must fight them as they fight us: an eye for an eye and a tooth for a tooth. I apologize that women had to witness this today, but in our land, our women have to see the same. You people will never be safe. Remove your government. They don’t care about you.”

The man and another suspect reportedly stayed at the scene of the attack, where they tried to engage in similar exchanges with bystanders. They were later shot and detained by British police. The attack occurred near a British military site that has deployed soldiers to both Iraq and Afghanistan.

The Obama administration is vowing to increase military aid for Syria’s armed rebels unless President Bashar al-Assad complies with demands for talks. Secretary of State John Kerry issued the threat at a “Friends of Syria” meeting in Jordan.

Secretary of State John Kerry: “In the event that we can’t find that way forward, in the event that the Assad regime is unwilling to negotiate Geneva 1 in good faith, we will also talk about our continued support and growing support for the opposition in order to permit them to continue to be able to fight for the freedom of their country.”

The United States and Russia are expected to convene a global conference on the Syrian conflict in the coming weeks.

The Chicago Board of Education has approved a plan to carry out the largest mass school closing in U.S. history. On Wednesday, the board voted to close 50 public schools, most of them in Hispanic and African-American neighborhoods. Together they account for close to 10 percent of Chicago’s elementary schools. Chicago Mayor Rahm Emanuel has pushed for the closures, citing a $1 billion deficit. Chicago teachers and parents have led a vocal campaign in protest, staging rallies and filing a lawsuit last week accusing the city of discriminating against affected students. In a statement, Chicago Teachers Union head Karen Lewis said: “Closing schools is not an education plan. It is a scorched earth policy.”

A sergeant at West Point Military Academy has become the latest Army official to be charged for sexual misconduct. Sergeant Michael McClendon is accused of committing indecent acts, reportedly for videotaping female cadets in the shower. His case follows recent sex-related allegations against three separate military officials. All three served formal roles in the military’s effort to prevent sexual harassment and assault.

The head of the Internal Revenue Service division at the heart of the scandal over the targeted vetting of right-wing groups has refused to testify before Congress. Appearing before the House Oversight and Government Reform Committee, Lois Lerner denied wrongdoing, but invoked her constitutional right to avoid self-incrimination.

Lois Lerner: “I have not violated any IRS rules or regulations, and I have not provided false information to this or any other congressional committee. And while I would very much like to answer the committee’s questions today, I’ve been advised by my counsel to assert my constitutional right not to testify or answer questions related to the subject matter of this hearing.”

Lerner was the first IRS official to publicly acknowledge that right-wing groups were subjected to extra scrutiny in a flood of applications seeking charitable tax status. But questions have swirled around her role amidst reports she was made aware of the targeting as early as June 2011.

Colorado Gov. John Hickenlooper has stayed the execution of a death row prisoner by citing moral concerns about the death penalty. On Wednesday, Hickenlooper announced a temporary reprieve for Nathan Dunlap, Colorado’s longest-serving death row inmate. Dunlap was scheduled for execution in August for a 1996 quadruple murder. In a statement, Hickenlooper said: “It is a legitimate question whether we as a state should be taking lives. Because the question is about the use of the death penalty itself, and not about [Dunlap], I have opted to grant a reprieve and not clemency in this case.”