U.S. President Barack Obama and NATO chief Anders Fogh Rasmussen on Wednesday spoke out in favor of strengthening the alliance's role in eastern Europe following Moscow's takeover of Crimea.

"We do not seek confrontation but we will not waiver if challenged," Rasmussen said after a brief meeting with Obama in Brussels, the Belgian capital that also hosts EU and NATO headquarters.

U.S. President Barack Obama urged the West on Wednesday to stand firm in opposing Moscow's takeover of Crimea, saying that "with time" Russians will realize "brute force" cannot win.

Winding up a daylong visit that kicked off with a moving tour through the only Belgian World War I cemetery to hold U.S. graves, Obama said "we must never forget that we are heirs to a struggle for freedom."

Tokyo Wednesday hailed the first summit between Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-Hye as a chance for the leaders to build a rapport after more than a year of backbiting.

The talks in The Hague were hosted by U.S. President Barack Obama, whose administration is increasingly frustrated by incessant sniping between its two major Asian allies.

Three Secret Service agents protecting President Barack Obama in Amsterdam this week were sent home and put on leave after a night of drinking, The Washington Post reported.

"One of them was found drunk and passed out in a hotel hallway," the Post reported, citing three unnamed people familiar with the case.

The White House said Tuesday it is "very disappointed" that Saudi Arabia has denied a Jerusalem Post reporter's visa to cover President Barack Obama's visit to the kingdom later this week.

Deputy national security adviser Ben Rhodes said the White House made clear to the Saudis the importance that the reporter have access to cover the trip.

The United States has said that North Korea's test firing of two medium-range missiles into the Sea of Japan represents "a troubling and provocative escalation" on the Korean Peninsula.

America is closely coordinating with allies and partners, including in the U.N. Security Council, "to take the appropriate measures in response" to Pyongyang's latest "violation of U.N. Security Council resolutions," the State Department said.

U.S. President Barack Obama on Tuesday hit out at Moscow's expansionism as a "sign of weakness" after Russia took control of the Crimean peninsula from Ukraine, fueling fears of further intervention in the region.

"Russia is a regional power that is threatening some of its immediate neighbors, not out of strength but out of weakness," Obama told journalists after a nuclear security summit in The Hague.

U.S. President Barack Obama on Tuesday pledged his "unwavering commitment" in the face of nuclear-armed North Korea as he hosted a landmark Japan-South Korea summit.

"The U.S. commitment to the security of both Japan and the Republic of Korea is unwavering... and a nuclear North Korea is unacceptable," Obama told the meeting in The Hague.

Thirty-five countries on Tuesday committed to bolstering nuclear security, backing a global drive spearheaded by U.S. President Barack Obama to prevent dangerous materials falling into the hands of terrorists.

In a joint statement issued on the sidelines of the third biennial Nuclear Security Summit (NSS), the countries pledged to work closer together and submit to "peer reviews periodically" of their sensitive nuclear security regimes.

Japan is to give up to $1.5 billion in financial aid to Ukraine, the government in Tokyo confirmed Tuesday, as the club of rich nations booted Russia off the membership list.

Prime Minister Shinzo Abe announced the figure as he and fellow world leaders, including U.S. President Barack Obama, cancelled an upcoming G8 meeting in Sochi, and said it would be replaced by a G7 event that did not involve Moscow.