The United States on Monday denounced as "unconscionable" threats made against the Libyan prime minister and cabinet members, saying the country needed to move forward.

"At a time when Libya most needs political consensus to move forward its democratic transition, extortion by physical attack must not hijack the process of peaceful dialogue," State Department spokeswoman Jen Psaki said in a statement.

Attacks on police and security service buildings in eastern Ukraine by pro-Russian gunmen bore "tell-tale signs of Moscow's involvement," the U.S. envoy to the United Nations said Sunday.

Speaking on ABC television's "This Week" program, Ambassador Samantha Power dismissed suggestions that the attacks, which have triggered gun battles with Ukrainian special forces, were the work of grass-roots militia groups.

Two prominent U.S. senators introduced legislation Friday that would remove Iraqi Kurdish organizations KDP and PUK from a terrorist blacklist.

The Obama administration supports the move, which officials have said requires legislative action rather than an executive order from the White House.

Washington on Wednesday denounced as "unfortunate" an order from Israeli Prime Minister Benjamin Netanyahu to limit his cabinet's contacts with their Palestinian counterparts.

"We are certainly aware of the announcement. We regard it as unfortunate," State Department spokeswoman Jen Psaki said, as her boss John Kerry met with Israeli Foreign Minister Avigdor Lieberman.

The United States on Tuesday asked North Korea to look at Iran's example, saying it was willing to negotiate with a hostile nation when it is "serious" about its promises.

Amid high tensions between North Korea and its neighbors, Deputy Secretary of State William Burns said that the United States remained firmly opposed to North Korea's nuclear weapons program but was open to diplomacy.

The Pentagon confirmed Monday that the United States is sending a guided missile destroyer to the Black Sea in order to reassure European allies in the region following Russia's annexation of Crimea.

"We have decided to send a ship into the Black Sea. We expect it will arrive there within a week," said Pentagon spokesman colonel Steven Warren, without disclosing the name or type of the vessel citing "operational security."

The United States has issued a license allowing Boeing to do business with Iran for the first time since the U.S. embargo of 1979, a company spokesman told Agence France Presse Friday.

The license covers a "limited period of time" and allows Boeing only "to provide them spare parts that are for safety purposes."

The United States said Thursday it has voiced concern to Iran on its potential selection of a U.N. ambassador with alleged links to the 1979 seizure of the U.S. embassy.

Iran has not announced a nominee to be its ambassador in the United Nations. But a U.S. senator critical of U.S. outreach to Iran said that the Islamic republic has sought a visa for Hamid Aboutalebi, who joined a student group behind the hostage-taking.

The confirmed death toll from a huge U.S. landslide rose to 29 Wednesday including three children, officials said a week and a half after the disaster in Washington state.

Twenty people are still believed missing after a wall of mud and debris crashed down on the town of Oso on March 22.

China should press North Korea to give up its nuclear weapons if Beijing wants to change U.S. troop plans in the region, a U.S. official said Tuesday.

Danny Russel, the assistant secretary of state for East Asia, acknowledged that a growing China has been unhappy with efforts by the United States to strengthen defense cooperation with allies Japan and South Korea.