The United States has used a secret channel to warn Iran's leaders against closing the strategic Strait of Hormuz, saying that doing so would provoke a U.S. response, the New York Times reported.

Iran has threatened to close the narrow and strategic waterway -- a chokepoint for one fifth of the world's traded oil -- in the event of a military strike or the severe tightening of international sanctions.

Mali's army has deployed extra troops and military equipment to its largely-desert north where Al-Qaida in the Islamic Maghreb operates, officials said Friday.

"The Malian army has deployed men, equipment and over 200 vehicles to the north," an administrative source said.

A mob killed two people and burnt mosques and homes in an overnight raid on a mainly Muslim village in northeastern Nigeria in the latest such violence to hit the country, residents said Friday.

"It was around 11:30 pm (22:30 GMT) when a crowd from Imbur attacked Gwalam village, setting fire on homes and mosques," resident Abubakar Hussaini said, with Imbur a largely Christian area and Gwalam mainly Muslim.

A high-level U.N. nuclear agency delegation will visit Iran in late January to try to clear up allegations of a covert weapons program and soothe tensions between Tehran and the West, diplomats said Friday.

The visit for talks led by International Atomic Energy Agency (IAEA) chief inspector Herman Nackaerts would last from the 28th through the first week of February, a Western diplomat told Agence France Presse.

Turkish police launched a nationwide swoop on alleged sympathizers of Kurdish separatist rebels and arrested more than 20 people, broadcaster NTV and other media outlets said.

The operation included a raid on the Ankara office of Leyla Zana, a Kurdish lawmaker known for her pro-independence views, the television channel said.

The U.S. embassy in Bangkok warned Friday of a possible terrorist threat against tourists in the Thai capital, urging its citizens to exercise caution in areas popular with foreigners.

"Foreign terrorists may be currently looking to conduct attacks against tourist areas in Bangkok in the near future," it said in an emergency message posted on its website.

Japan is "extremely circumspect" about the U.S.-led drive to impose sanctions on Iranian oil exports, the country's foreign minister said Friday, apparently contradicting an earlier pledge to join Washington's campaign.

"The United States would like to impose sanctions. We believe it is necessary to be extremely circumspect about this matter," Koichiro Gemba told a press conference.

Two of Washington's top irritants, Mahmoud Ahmadinejad and Fidel Castro, discussed world events for two hours, and the Iranian leader on Thursday described the retired Cuban revolutionary as healthy and engaged, and declared their two countries to be allies "fighting on the same front."

"It made me enormously happy to see the comandante healthy and fit," Ahmadinejad said through a translator at an impromptu airport appearance alongside Fidel's brother, Cuban President Raul Castro, before flying off to Ecuador for the final stop in his four-nation Latin America visit.

New sanctions against Iran will be perceived by the world community as an attempt at changing the regime in the Islamic republic, Russia's Deputy Foreign Minister Gannady Gatilov said on Friday.

"Additional sanctions against Iran, as well as potentially any military strikes against it, will unquestionably be perceived by the international community as an attempt at changing the regime in Iran," Gatilov was quoted as saying by Interfax.

The United States plans to withdraw about 7,000 U.S. troops of the 81,000 troops based in Europe, U.S. Defense Secretary Leon Panetta said Thursday.

In an interview with the Armed Forces Press Service, Panetta said two brigade combat teams, or roughly 7,000 U.S. troops, would be withdrawn from Europe, but rotational units would still maintain strong military presence in the region.