Ukraine says it has launched an operation to retake government buildings from pro-Russian separatists in the country’s east. Despite the announcement, it appears no troops have moved in so far. On Monday, the separatists seized even more buildings after flouting the Ukrainian government’s deadline to lay down their arms. The Russian government is warning the crisis could spark a civil war. The United States, meanwhile, is threatening new sanctions on Russia. In a phone call on Monday, President Obama told Russian President Vladimir Putin to rein in the separatists, but Putin denied interfering in Ukraine. At the White House, Press Secretary Jay Carney said the United States is prepared to take new steps against Russia. He also confirmed a visit to Ukraine by CIA Director John Brennan but played down its importance.

White House Press Secretary Jay Carney: “I can assure you that Russia’s provocations, further transgressions and provocations, will come with a cost. … Senior-level visits of intelligence officials are a standard means of fostering mutually beneficial security cooperation, including U.S.-Russian intelligence collaboration going back to the beginnings of the post-Cold War era. U.S. and Russian intelligence officials have met over the years. To imply that U.S. officials meeting with their counterparts is anything other than in the same spirit is absurd.”

Also Monday, the Ukrainian government asked the United Nations to authorize a peacekeeping force for the restive east. Russia would likely veto the request should it come to a Security Council vote.

The death toll from Monday’s bombing of a bus station in Nigeria has topped 71, with more than 120 wounded. The station is just on the outskirts of the capital Abuja. The Nigerian government has blamed the militant group Boko Haram, which has staged a number of attacks in recent years.

Prosecutors say the suspect in this weekend’s deadly shootings at two Jewish centers in Kansas will face hate crimes charges. Frazier Glenn Miller is a known white supremacist with ties to neo-Nazi groups and the Ku Klux Klan. He has previously served time in prison on weapons charges and plotting to assassinate the founder of the Southern Poverty Law Center, which monitors extremist groups. Miller is accused of shooting three people dead at a Jewish community center and retirement home. On Monday, family members remembered 14-year-old Reat Underwood and his grandfather, William Lewis Corporon, who died in the attack.

Mindy Corporon: “He was with us for a wonderful 14 years. He had a really full life for a 14-year-old, and we were very blessed. And I’ve heard from his friends, and I’ve talked to his best friend, and they love him, too.”

Will Corporon: “Everybody wants to know how we’re doing. And to varying degrees, we’re muddling through. You know, no one thinks they’re going to have funerals to plan, and no one believes this will happen to you, to your family.”

At the White House on Monday, President Obama also paid tribute to the victims and spoke out against hate crimes.

President Obama: “As a government, we’re going to provide whatever assistance is needed to support the investigation. As Americans, we not only need to open our hearts to the families of the victims, we’ve got to stand united against this kind of terrible violence, which has no place in our society. And we have to keep coming together, across faiths, to combat the ignorance and intolerance, including anti-Semitism, that can lead to hatred and to violence.”

A Nevada rancher is declaring victory after hundreds of armed supporters backed his standoff with the federal government. The Bureau of Land Management began seizing Cliven Bundy’s cattle this month over his failure to pay more than $1 million in owed costs. Bundy’s cattle had grazed on federally controlled land for years, requiring him to pay government fees. But Bundy had refused to comply, saying he does not recognize the federal government’s existence. Local politicians and hundreds of people from right-wing, anti-government, and pro-gun groups flocked to Bundy’s side last week. Many were armed. Over the weekend, they shut down Interstate 15, leading to a standoff that ended with the government backing down and releasing the seized cattle. A local police official said the Bureau of Land Management wanted to avoid violence and public harm.

Officer: “We had a lot of fears of individuals being shot, individuals being trampled, individuals being run over on the highway. So, it took a lot of resources, a lot of resources for the taxpayers associated with this.”

On Monday, Bundy urged state sheriffs nationwide to join his cause and “take away the guns from the United States bureaucrats.” The South Poverty Law Center, which tracks right-wing extremists, has warned the standoff could encourage other anti-government groups to stage similar actions.

An Army general has denied the clemency bid of Chelsea Manning and upheld her 35-year prison sentence. Manning was seeking leniency for leaking a trove of classified U.S. documents to WikiLeaks, arguing it was done for the public good. With the general’s denial, Manning’s request will go to the Army Court of Criminal Appeals.

The military trial of five alleged 9/11 conspirators has been put on hold over allegations of FBI spying on their attorneys. The defense lawyers say the government has used a member of one of the suspects’ legal team as a confidential informant. The allegation follows previous claims by the attorneys that Guantánamo Bay prison officials have monitored their communications.

The Justice Department has announced it will not contest a court ruling that granted hunger-striking Guantánamo prisoners the right to challenge their force-feeding and other harsh conditions. The move clears the way for a number of pending challenges from Guantánamo prisoners and could lead to even more being filed.

A new report says the killings of environmental activists defending land rights has surged over the past decade. The group Global Witness says 147 activists were killed in 2012, compared to 51 in 2002. The death rate is now an average of two per week. Brazil was the world’s deadliest country for environmental defenders, with 448 deaths between 2002 and 2013. Honduras was second with 109 deaths over the same period.

Activists and landowners in Nebraska have unveiled a massive “crop art” opposing the Keystone XL pipeline. Using tractors, organizers dug into their corn fields an image of a rancher and a Native American with the inscription: “Heartland Equals No Keystone XL.” The image is said to be the size of 80 football fields.

The Guardian US and The Washington Post have won a Pulitzer Prize for their stories exposing National Security Agency surveillance. Handing out the award for public service journalism, the Pulitzer committee said the disclosure of mass spying “[helped] spark a debate about the relationship between the government and the public over issues of security and privacy.” The reporting was based on the leaks of whistleblower Edward Snowden, who shared NSA files with journalists Laura Poitras, Glenn Greenwald, Ewen MacAskill and Barton Gellman. The group also won a George Polk journalism award last week. In a statement, Snowden honored the journalists involved, saying: “This decision reminds us that what no individual conscience can change, a free press can. … Their work has given us a better future and a more accountable democracy.”