The United States imposed financial sanctions Friday on North Korea and several senior government officials in retaliation for a cyber attack on Hollywood studio Sony Pictures.

President Barack Obama said he ordered the sanctions because of "the provocative, destabilizing, and repressive actions and policies of the Government of North Korea, including its destructive, coercive cyber-related actions during November and December 2014."

Cuba's arrest of several dissident activists caused a new rift Wednesday with the United States, the first diplomatic scuffle since this month's historic announcement of a renewal in ties.

Washington condemned Havana's "lack of respect" for human rights after the communist authorities on Tuesday arrested leading figures expected at an open mic session convened for Cubans to speak out about their future.

The United States expressed concern Wednesday over the plight of several dissidents detained by Cuba, just two weeks after Washington's historic move to normalize relations with Havana.

"We are deeply concerned about the latest reports of detentions and arrests by Cuban authorities of peaceful civil society members and activists," the U.S. State Department said in a statement.

The European Union said a Russian court's conviction Tuesday of opposition leader Alexei Navalny and his brother seemed to be politically motivated, while calling for restraint during any protests against the verdict.

"The guilty verdict delivered today... against Alexei Navalny and his brother Oleg Navalny appears to be politically motivated," a spokeswoman for EU foreign policy chief Federica Mogherini said in a statement.

The United States named nine individuals and entities to its Iran sanctions blacklist Tuesday, most of them for helping Tehran obtain U.S. banknotes worth hundreds of millions of dollars.

The U.S. Treasury named five men from Iran and other countries, and Dubai-based company Belfast General Trading, for sanctions violations for their efforts to support the Iran government's acquisition of U.S. currency.

North Korea suffered a new Internet outage on Saturday shortly after calling U.S. President Barack Obama a "monkey" over the release of a comedy film about a fictional plot to kill its leader.

The latest shutdown came after the isolated dictatorship's powerful National Defence Commission (NDC) threatened "inescapable deadly blows" over the film and accused the U.S. of "disturbing the Internet operation" of media outlets after a blackout earlier this week.

North Korea threatened Sunday to hit back at the White House and other U.S. targets if Washington sanctions it for an alleged hacking attack.

At least 25,000 protesters paralyzed parts of New York and thousands more marched in Washington on Saturday, stepping up demonstrations across the United States demanding justice for black men killed by white police.

The rallies in the capital, New York, Boston and in several Californian cities were among the largest in a growing protest movement sparked by the killing of unarmed black teenager Michael Brown in Ferguson, Missouri on August 9.

A small jet airplane crashed Monday into a residential neighborhood near the US capital, killing six people.

The Embraer EMB-500 twin-engine jet was a mile away from Montgomery County Airport, preparing to land, when the accident occurred, according to a statement from the Federal Aviation Administration.

Britain's Prince William met U.S. President Barack Obama in the Oval Office on Monday as well-wishers braved the freezing cold to glimpse his pregnant wife, the Duchess of Cambridge, in New York.

The royal pair parted company on day two of their second visit as a couple to the United States as they mix diplomacy with supporting their favorite causes and promoting British business.