Bashar Fahmi, a Jordanian reporter working for the US-funded al-Hurra TV network, was last seen in one of Yamamoto's TV reports, when he was sitting behind her.
BBC: Syria conflict: Japan reporter Mika Yamamoto flown home
The Sahwa - or Awakening Council - are comprised of Sunni tribal members who sided with the US against al-Qaeda in 2006.
As a Principal Lead Author with the Inter-governmental Panel on Climate Change, he shared the 2007 Nobel Peace Prize with former US Vice-President Al Gore.
They were inspired by former US Vice-President Al Gore and were intended to raise awareness of climate change.
In public remarks last week, UAE Ambassador to the US Youssef al-Otaiba made a series of statements whose bluntness was unprecedented.
In 2007, he was recognised for his work as a Principal Lead Author of the Intergovernmental Panel on Climate Change (IPCC), sharing the Nobel Peace Prize with former US Vice-President Al Gore.
Imad al-Din Adib in the pan-Arab Saudi-owned Al-Sharq al-Awsat agrees that the killing of the US ambassador and three of his aides "is a humanitarian and political catastrophe" with implications for "Washington's ties with the region as a whole".
BBC: Anti-Islam film: Press views on West and Muslim world ties
In an earlier speech at the Pentagon, Vice-President Joe Biden praised the US soldiers who had killed al-Qaeda leader Osama Bin Laden in Pakistan in May of this year.
BBC: 9/11 anniversary: Sombre US honours victims 10 years on
There are about 18, 000 US-led foreign troops in Afghanistan tracking al-Qaeda and Taleban militants, with security patchy outside the capital Kabul.
Analysts say the US has wanted al-Shabab banned from Twitter for some time, but lacked the legal means to enforce its will.
The memo says, among other things, that Iraq and Afghanistan will be a "long, hard slog", and that the US record against al-Qaeda is mixed.
The US has put al-Nusra on a blacklist of terrorist organisations.
Jordanian intelligence believed they had brought Humam al-Balawi over to their side and sent him to Afghanistan to infiltrate al-Qaeda, US network NBC says.
Mr Obama reiterated the US goal of destroying the remnants of al-Qaeda, and said the US had come close to achieving that.
BBC: US troops will end 'most' Afghanistan combat this spring
In May 2008, Sgt Petry's unit of elite Army rangers approached a house in Paktia province in eastern Afghanistan which intelligence suggested held high-value al-Qaeda officials, the US military said.
BBC: Afghanistan veteran Leroy Petry given US Medal of Honor
His defence secretary, Leon Panetta, earlier told the BBC the US would go after al-Qaeda wherever they tried to hide.
Laura Hammond, senior lecturer in development studies at the School of Oriental and African Studies (Soas) in London, said the US had wanted the al-Shabab account closed for some time, but had lacked the legal means to force Twitter to act.
Shortly after Ethiopian forces took control of Mogadishu, US aircraft pursued fleeing al-Qaida terrorists in southern Somalia after intelligence reports indicated that among the fleeing ICU leaders were the masterminds of the 1998 bombings of the US embassies in Nairobi and Dar es Salaam.
British actor Lewis has said he drew inspiration for his character - a US marine freed after eight years as an al Queda captive - from Brian Keenan's 1991 book An Evil Cradling.
Both Turkey and the US oppose Syrian President Bashar al-Assad, with Turkey holding that the West should do more to help the Syrian opposition.
Mr Karzai added that during his last visit to Washington, the US had said it considered al-Qaeda, rather than the Taliban, as the real enemy.
BBC: Karzai speech 'put Nato forces at risk', commander warns
Days later, US forces delivered the first al-Qaeda suspects to Guantanamo.
BBC: Foreign Office officials 'backed Guantanamo detentions'
Musharraf believed that he could play a double game of at once helping the US in Afghanistan and sheltering al-Qaida and the Taliban in Pakistan.
In 2007, Mr Maliki authorised a surge in US troop numbers that targeted al-Qaeda affiliated Sunni militants and led the 2008 campaign against Shia militias loyal to the radical cleric, Moqtada Sadr.
Turkey and the US both oppose Syrian President Bashar al-Assad, but differ on how best to support the opposition.
As the US calls for Syrian President Bashar al-Assad to step down, it has also expressed concern about militant groups fighting in Syria.
At that time President Musharraf had become a valued US ally in the fight against al-Qaeda and was making peace with nuclear-armed rival India.
But it suggests he will not plead guilty to aiding enemies of the US (identified by prosecutors as al-Qaeda in the Arabian Peninsula), violating federal espionage and computer laws - charges for which he could face life in prison if found guilty.
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