Envoys of U.S. President Barack Obama voiced "deep concern" at violence and the humanitarian crisis on the border of Sudan and South Sudan during a visit to the region, the White House said Monday.

Deputy National Security Advisor Denis McDonough joined Washington's special envoy for Sudan, Princeton Lyman, for talks in Khartoum and then in Juba, the capital of newly independent South Sudan, on Sunday and Monday.

Iran on Tuesday blasted new sanctions against the Islamic republic announced by the United States, Britain and Canada as "reprehensible and ineffective."

Foreign ministry spokesman Ramin Mehmanparast made the comments a day after Washington, London and Ottawa said they were leveling additional sanctions on Iran's financial sector because of a report by the U.N. atomic energy watchdog strongly suggesting Tehran was researching nuclear weapons.

The United States is to unveil new sanctions against Iran Monday targeting its financial, oil and petro-chemical sectors, according to briefings by U.S. officials to several American news outlets.

The reported sanctions aim to up the pressure on Tehran over its nuclear program after a report by the U.N. atomic energy watchdog strongly suggesting Iran was researching nuclear weapons.

Russia's point man on Africa said Saturday that Moscow was relieved that murdered Libyan strongman Moammar Gadhafi's son Seif al-Islam had been arrested and had escaped "summary justice".

"We are happy that this time the new authorities in Libya did not resort to summary justice for Seif al-Islam, the son of the ousted leader Gadhafi," the Russian presidency's special representative for Africa Mikhail Margelov said.

Premier Wen Jiabao told U.S. President Barack Obama that China would increase the flexibility of the yuan while stressing that reforms had already had an effect, state television reported Saturday.

"We are closely watching the changes to the yuan's exchange rate ... and will encourage the yuan's flexibility in both directions," CCTV quoted Wen as saying at a meeting with Obama on the sidelines of the East Asia Summit in Indonesia.

President Barack Obama on Friday hailed the East Asia Summit as the top forum for tackling the region's seething maritime row with China, setting a course for confrontation with Beijing.

The Chinese government has testily declared the South China Sea dispute off-limits at Saturday's talks, to be attended by Obama, China's Premier Wen Jiabao, and 16 other nations including several with claims over the waterway.

The United States on Thursday disagreed with Russia's assessment that attacks by renegade Syrian troops risked plunging Syria into civil war, blaming the regime in Damascus for the violence.

"We think that's an incorrect assessment," U.S. State Department deputy spokesman Mark Toner told reporters after Russian Foreign Minister Sergei Lavrov made the assessment.

The United States said Wednesday that the use of violence by the Syrian opposition plays into the Syrian "regime's hands," adding it did not condone violent acts by either side.

State Department deputy spokesman Mark Toner was reacting to reports that Syrian army defectors had attacked a Syrian military intelligence base on Wednesday in one of the most daring raids in eight months of unrest.

President Barack Obama said the United States and Russia would seek a "common response" to Iran's nuclear challenge, despite strong reservations about new sanctions expressed by Moscow.

After meeting Russian President Dmitry Medvedev, Obama said the sides "reaffirmed our intention to work to shape a common response so we can move Iran to follow its international obligations when it comes to its nuclear program."

A radical group in Yemen announced on Wednesday that a film will be produced documenting the life of slain U.S.-born cleric Anwar al-Awlaqi and which will include a previously unknown message to Americans.

Partisans of Sharia (Islamic law) said "a film on Awlaqi's life will be produced in both Arabic and English on his role in reviving the rite of jihad (holy war) in the hearts of many Muslim youths, especially in Arab societies," the al-Qaida linked group said in a statement.