The U.S. government has more than doubled, to $25 million, its reward offered for information on the whereabouts of Islamic State leader Abu Bakr al-Baghdadi, placing him in a category whose only other occupant is Ayman al-Zawahiri, the leader of al-Qaeda.

Since an initial $10 million was first offered in 2011 by the State Department-administered Rewards for Justice program, the Islamic State has seized control of large portions of Syria and Iraq and “gained the allegiance of jihadist groups and radicalized individuals around the world, and has inspired attacks in the United States,” according to a U.S. “Wanted” poster.

The increased reward does not come with any indication that U.S. intelligence has a firm idea of where Baghdadi is located. The last confirmed sighting of him was in the Iraqi city of Mosul in the summer of 2014, shortly after Islamic State militants occupied the city. Since then, he has released several audiotapes exhorting his troops to fight on, and U.S. officials have variously indicated he is believed to be hiding in Mosul, or in the Islamic State-occupied city of Raqqa, Syria.

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U.S.-aided Iraqi troops have gained back much of the territory lost to the militants and are in the midst of a massive offensive to retake Mosul. In Syria, the picture is mixed, with U.S. Special Operations forces guiding recruited Syrian fighters now encircling Raqqa, while the militants this week retook the city of Palmyra, where they were ousted by Syrian troops and Russian airstrikes last year.

U.S. and coalition airstrikes have killed a number of senior Islamic State leaders this year, and “eventually we will find and eliminate him as well,” Brett McGurk, the administration’s special envoy to the coalition, said this week. “Issuing audiotapes deep in hiding is not really a sign of a confident leader, particularly in today’s media age.”

The Islamic State is considered far more flexible than al-Qaeda, which found its leadership ranks hard to replenish. But because Baghdadi claims to be the “caliph” of his self-declared caliphate, “I definitely think that when we do eliminate Baghdadi it will make a significant difference,” McGurk said.

“He is somewhere in hiding,” McGurk said, “and we also know he hides with slaves and all sorts of terrible things. This guy is one of the most despicable we’ve ever seen.”

While the Obama administration would like to eliminate Baghdadi before leaving office, a State Department official said that the process to increase the reward is “very deliberative” and has been underway for some time.

There are 29 people on the Rewards for Justice list. After Baghdadi and Zawahiri, the next highest offer, $10 million, covers three figures — Afghan Sirajuddin Haqqani, tied to al-Qaeda and the Taliban; Hafiz Saeed,

the founder of the Pakistani terrorist group Lashkar-e-Taiba; and ­Yasin al-Suria Pakistani, a ­Syrian-born senior al-Qaeda leader.

Rewards for Justice was established in 1984 for terrorism suspects. Although decisions on who is included is ultimately authorized by the secretary of state, recommendations are made by a committee with ­representatives from various ­national security departments and agencies.

Awards are normally kept secret, although the State Department has said that the largest ever paid, $30 million, went to an individual who provided information leading to Uday and Qusay Hussein, the sons of former Iraqi president Saddam Hussein.