Profiles of wanted 'Islamic State leaders'
The US Department of State is offering rewards totalling $20m (£13m) for information on four men identified as leading figures in the jihadist group, Islamic State (IS).
While two of the men - spokesman Abu Mohammed al-Adnani and battlefield commander Tarkhan Tayumurazovich Batirashvili - have public profiles and are widely known as senior IS figures, the other two have never been mentioned in IS media output.
Some sources, including prominent Iraqi security analyst Hisham al-Hashimi and Arabic media, have identified one of the men, Abdul Rahman Mustafa al-Qaduli, as Abu Alaa al-Afari.
Last month, unconfirmed reports said Afari had taken temporary charge of IS while its leader, Abu Bakr al-Baghdadi, recovered from a spinal injury sustained in an air strike in Iraq in March.
The image being circulated of Qaduli is the same used last month in connection with Afari.
Qaduli, who was born in 1957 or 1959 in Iraq's second city of Mosul, is described by the state department as a "senior IS official". He joined the group's forces in Syria after his release from prison in 2012, according to the US Rewards for Justice programme.
He had joined al-Qaeda in Iraq (AQI) - a precursor of IS - in 2004 under the leadership of the late Abu Musab al-Zarqawi, serving as his deputy and the local leader in Mosul.
Syrian-born Abu Mohammed al-Adnani is Islamic State's official spokesman, responsible for disseminating many of the group's messages. It was Adnani who delivered the group's declaration on the creation of a "caliphate" last June.
Born Taha Sobhi Falaha in the northern Syrian town of Banash in 1977, US officials say he was one of the first foreign fighters to oppose the presence of US-led forces in Iraq after the 2003 invasion.
Tarkhan Tayumurazovich Batirashvili, also known as Omar Shishani - "Shishani" means Chechen in Arabic - is an IS military commander based in northern Syria. The US says he was placed in charge of IS military operations in Aleppo, Raqqa, Latakia and Idlib provinces in May 2013, and has held a number of top military positions within the group.
As of late 2013, he was the IS emir (leader) for northern Syria and was located in and around Aleppo Province. He was also in charge of fighters from Chechnya and elsewhere in the North Caucasus.
For some time, Shishani was considered a "poster boy" for IS, frequently appearing in its propaganda material with his distinctive red beard. However, since late last year, news of his role in battles in Syria has dried up.
Before joining IS in 2013, Shishani was leader of Jaysh al-Muhajirin wa al-Ansar (Army of the Emigrants and Helpers), an al-Qaeda-linked group that comprised hundreds of mostly foreign fighters, many of them from the North Caucasus.
Shishani is said to have previously served in the Georgian army and has also spent time in prison. He was born in 1986 in the village of Birkiania in Georgia's north-eastern Pankisi Valley.
Tariq bin al-Tahar bin al-Falih al-Awni al-Harzi is a high-profile IS member operating in Syria.
Born in Tunis in 1982, he is emir for the border region between Syria and Turkey and has worked to recruit and facilitate the travel of foreign fighters for IS since 2013, according to US officials. He and several other IS border group members assisted foreign fighters from the United Kingdom, Albania, and Denmark.
Since late 2013, Harzi has also been "emir of suicide bombers" and played a central role in suicide and vehicle-borne improvised explosive device (VBIED) attacks in Iraq, the US says.
Harzi has helped raised funds from Gulf-based donors for IS, including $2m from a Qatar-based facilitator, and been involved in the planning of foreign operations.