A senior North Korean official is due to visit the United States amid signs of an easing of relations between the two countries, a report said Monday.

Ri Jong-Hyok, vice chairman of the Korea Asia-Pacific Peace Committee, has been allowed to attend a forum at the University of Georgia on October 17-20, Yonhap news agency said.

The younger brother of U.S. Vice President Joe Biden spent the night in hospital after opening a package from India that contained white powder initially feared to be anthrax, reports said Sunday.

Francis Biden, 57, told local media in southern Florida that his girlfriend Mindy had retrieved a large Manila envelope addressed to him from their roadside mailbox in Ocean Ridge at about noon on Saturday.

The United States warned its nationals Saturday of "potential for retaliation" after two key Al-Qaeda figures were killed in an air raid in Yemen.

The State department issued a global travel alert to U.S. citizens, a day after Washington confirmed that U.S.-Yemeni citizen Anwar al-Awlaqi, the external operations leader of Al-Qaeda in the Arabian Peninsula (AQAP), was killed.

Iran's offer to halt production of low enriched uranium is not credible because the Islamic republic has a record of making "empty promises," the United States said Friday.

The United States said Friday it summoned the Syrian ambassador to Washington to read him "the riot act" after President Bashar al-Assad's supporters tried to attack the U.S. envoy in Damascus.

U.S. President Barack Obama said Friday the killing of U.S-born cleric Anwar al-Awlaqi was "major blow" to Al-Qaida's Yemeni franchise and vowed to be relentless in destroying global terror networks.

A U.S. follower of al-Qaida was arrested Wednesday on charges of planning to fly explosive-packed, remote controlled airplanes into the Pentagon and the U.S. Capitol, authorities said.

Rezwan Ferdaus, 26, was arrested and charged with the aerial bombing plot to attack Washington and attempts to deliver bomb-making materials for use against U.S. troops in Iraq, U.S. Attorney Carmen Ortiz said in Boston.

The White House Wednesday treated an Iranian claim that it would send ships close to U.S. waters with derision, saying it did not reflect Tehran's ability to project sea power far from its shores.

"We don't take these statements seriously, given that they do not reflect at all Iran's naval capabilities," President Barack Obama's spokesman Jay Carney said.

China on Wednesday warned the United States against interfering in its affairs after two Buddhist monks set themselves on fire and the U.S. called for Beijing to respect the rights of Tibetans.

The U.S. State Department said Tuesday it was "seriously concerned" by attempts by two monks at the Kirti monastery in southwest China's Sichuan province to burn themselves to death in an apparent call for religious freedom.

Iran's navy is going to deploy ships close to US territorial waters, its commander in chief was quoted as saying on Tuesday.

"As the global oppression (the U.S.) is present not far from our maritime border ... our navy is going to have a strong presence not far from U.S. territorial waters," the Irna news agency quoted Admiral Habibollah Sayyari as saying.