U.S. President Barack Obama pledged Wednesday a "steadfast" commitment to defend Japan, including preventing nuclear attacks on his ally in the wake of North Korea's third nuclear test, the White House said.

In a telephone call, Obama and Japanese Prime Minister Shinzo Abe discussed steps to respond to the "highly provocative violation of North Korea's international obligations, a White House statement said.

A U.S. military officer said Wednesday that he felt under pressure when tasked to screen the mail of five men held at Guantanamo Bay on suspicion of plotting the September 11 attacks.

On the third day of a preliminary hearing at the U.S. naval base located at the southeastern tip of Cuba, lieutenant Alexander Homme testified via video link about how communications of so-called "high-level" detainees were handled.

Iran agreed on "some points" in talks with experts from the U.N. atomic watchdog in Tehran on Wednesday, its lead negotiator at the meeting said, quoted by local media.

"Some differences were resolved and agreement on some issues in the modality was reached," Ali Asghar Soltanieh, Iran's envoy to the International Atomic Energy Agency (IAEA), was quoted as saying by ISNA news agency.

U.S. Defense Secretary Leon Panetta discussed "immediate coordinated actions" with his South Korean counterpart on Wednesday, after North Korea staged a third nuclear test, a Pentagon spokesman said.

Panetta spoke with South Korea's Defense Minister Kim Kwan-Jin one day after Pyongyang triggered international outrage bay carrying out its latest nuclear detonation in defiance of U.N. Security Council resolutions.

U.S. Secretary of State John Kerry Wednesday urged "strong, credible" response from world leaders after North Korea's nuclear test to show Iran that they are serious about non-proliferation.

"This is about proliferation and this is also about Iran ... because they're linked. You connect the dots," Kerry said after talks with Jordanian Foreign Minister Nasser Judeh.

At least four people died when an Antonov AN-24 plane with dozens of football fans on board made an emergency landing Wednesday in the eastern Ukraine city of Donetsk, officials said.

"Most passengers have been rescued. Right now, we have four dead," local governor Andrey Shyshatsky told reporters at the airport.

The U.S. government has not denied health insurance to the Navy SEAL who killed Osama bin Laden despite a magazine article that implied otherwise, officials said Wednesday.

In a lengthy profile this week in Esquire magazine, the commando -- whose identity was kept secret -- is portrayed as a neglected hero who must buy private health insurance and struggle to earn income after retiring from a 16-year career in uniform.

European Union foreign policy chief Catherine Ashton on Wednesday said she hoped Iran would show some "flexibility" at upcoming talks with world powers on its nuclear program in Kazakhstan.

Iran and the so-called P5+1 -- Britain, China, France, Russia, the United States and Germany -- are due to resume discussions in Almaty on February 26, after a months-long break and failed meetings in Istanbul, Baghdad and Moscow.

Turkey's Islamic-rooted government is set to submit a new legal package that would tune its often criticized anti-terrorism laws to European standards, parliamentary sources said Wednesday.

"The changes we have prepared will enable Turkey to move forward in the path of the rule of law and expand freedom of expression," said Justice Minister Sadullah Ergin.

French construction firms Vinci and Bouygues said Wednesday they had evacuated as a precaution around 80 employees from the Chernobyl nuclear power plant in Ukraine after a section of the roof collapsed.

The two companies are working on constructing the sarcophagus structure covering the reactor that exploded in 1986 in the world's worst nuclear disaster.