The FBI opened an investigation into the death of a black man whose body was found hanging Thursday from a tree in the southern US state of Mississippi, officials said.

The discovery of the body garnered considerable national media attention, coming at a time of heightened tensions and sensitivities around race in the United States.

The United States is looking into allegations that the Syrian regime unleashed chlorine gas in an attack in the northwest of the war-ravaged country earlier this week, John Kerry said Thursday.

"While we cannot yet confirm details, if true, this would be only the latest tragic example of the Assad regime's atrocities against the Syrian people," the top U.S. diplomat said in a statement, warning the international community would not "turn a blind eye to such barbarism."

The White House on Thursday raised the prospect of withdrawing crucial diplomatic cover for Israel at the United Nations, following Benjamin Netanyahu's divisive election victory.

Angered by Netanyahu's shock campaign pledge to block the creation of a Palestinian state, the White House warned the foundation of its policy for backing Israel had been undermined.

U.S. Secretary of State John Kerry and his Iranian counterpart Thursday hailed "progress" in marathon nuclear talks but Washington denied a draft deal was already being circulated.

A European negotiator said meanwhile that Iran and six major powers -- the U.S., China, Russia, Britain, France and Germany -- remained "pretty far from a deal" ahead of a March 31 deadline to agree the outlines of an agreement.

Russia said Thursday it had doubled the number of troops taking part in mass drills ordered by President Vladimir Putin this week to 80,000 in a major show of strength amid tensions with the West over Ukraine.

Putin on Monday ordered drills for more than 40,000 troops in regions spanning the country, from the Arctic to the far east to the volatile southern Caucasus, and ordered nuclear bomber jets to be deployed in Crimea a year after its annexation by Moscow.

Al-Qaida's Yemen affiliate claimed responsibility for the murder of an award-winning journalist turned top official of the Shiite Huthi militia, the group said Thursday on Twitter.

The claim was made by Ansar al-Sharia, or Partisans of Sharia (Islamic law), which is linked to the Sunni extremist al-Qaida in the Arabian Peninsula (AQAP).

The Mexican Navy stepped up patrols off the Pacific coast resort of Cabo San Lucas after a group of U.S. and European tourists camping on an island were robbed and left stranded.

Navy forces will also carry out patrols on beaches themselves in Baja California state, the Navy said in a statement.

Central Bank Governor Riad Salameh downplayed on Thursday Washington's concerns on the possibility of involving Lebanese banks in money laundering operations to finance terrorism, in particular the Islamic State of Iraq and the Levant (ISIL).

“Lebanon's banks are fortified due to the strict measures imposed by the Central Bank and the monitoring bodies,” Salameh stressed in comments published in al-Mustaqbal newspaper.

South Korea and the United States will launch a massive landing drill next week, the climax of an ongoing joint military exercise which North Korea views as an invasion rehearsal.

The amphibious drill will start March 28 and run until April 1 at the port of Pohang, some 360 kilometers (223 miles) south of Seoul, the U.S.-South Korea Combined Forces Command said in a statement.

Syria's military said Wednesday it downed an American drone over suspicions it was spying, in what would be its first attack on an aircraft in the U.S.-led coalition battling jihadists.

A military source, speaking to AFP on condition of anonymity, said the drone was not immediately identified as being American but was shot down as a hostile aircraft.