Tension with Iran and "uncertainty" in the region is adding a $20 or $30 premium to oil prices, pushing up gas prices for vehicle owners in the United States, President Barack Obama said.

"The key thing that is driving higher gas prices is actually the world's oil markets and uncertainty about what's going on in Iran and the Middle East, and that's adding a $20 or $30 premium to oil prices," Obama said in an interview with the American Automobile Association (AAA) published Friday.

The United States on Friday named the president of a prestigious Ivy League college, Jim Yong Kim, to lead the World Bank, in a race challenged by developing country candidates.

"It's time for a development professional to lead the world's largest development agency," Obama said flanked by Kim, a Korean-American and the head of Dartmouth College.

The international community will subsidize Afghan security forces by more than $4 billion a year for a decade after U.S.-led combat forces leave Afghanistan in 2014, President Hamid Karzai said Thursday.

Western officials told Agence France Presse that no final agreement had been reached.

Turkey's energy minister said Wednesday negotiations were under way to earn waivers from U.S. sanctions on crude oil imports from neighboring Iran.

"Currently talks are being conducted at the level of companies," Taner Yildiz was quoted as saying by the Anatolia news agency.

The United States said Tuesday it was exempting European Union members and Japan from tough new sanctions on Iran, praising them for reducing dependency on oil from the Islamic republic.

Under a new law aimed at pressing Iran over its nuclear program, the United States will penalize foreign financial institutions over transactions with Iran's central bank, which handles sales of the country's key export.

Iran's supreme leader, Ayatollah Ali Khamenei, warned on Tuesday his country would hit back at any attack by the United States or Israel, firming tensions in the showdown over Tehran's nuclear program.

"We have said that we do not have atomic weapons and we will not build any. But if there is any attack by the enemies, whether it be United States or the Zionist regime, we will attack them at the same level as they attack us," he said in a live televised speech to mark the start of the Iranian new year.

U.S. President Barack Obama, in a holiday message Tuesday to the Iranian people, said that the two nations despite their tensions share a "common humanity," as he pressed for greater freedom for those living in Iran.

"There is no reason for the United States and Iran to be divided from one another," Obama said in a statement to Iranians on Nowruz, the Persian New Year, adding that "the Iranian people are denied the basic freedom to access the information that they want."

A Pakistan parliamentary committee on Tuesday demanded an unconditional apology from the United States for a November air attack on its border post that killed 24 soldiers.

Parliament opened a debate on recommendations drawn up by the parliamentary committee on national security which called the attack a "blatant violation of Pakistan's sovereignty and territorial integrity."

A top U.S. Department of the Treasury official is expected to urge Lebanon on Tuesday to abide by the U.S. and European Union sanctions imposed on Syria, Lebanese dailies said.

An Nahar newspaper quoted political sources as saying that Under Secretary for Terrorism and Financial Intelligence David Cohen will urge Central Bank Governor Riyad Salameh and other high-ranking officials to prevent Lebanese banks from offering any support that would help the Assad regime escape the sanctions.

A U.S.-born Islamist fighter viewed as a key foreign leader within Somalia's al-Qaida allied Shebab militia has said he fears his life is now in danger from fellow extremists.

Omar Hamami -- better known as Abu Mansoor al-Amriki -- gave the warning in an undated video posted on several Somali websites and YouTube Saturday.