Battling Islamic State

Iraqi Shiite fighters patrol around the town of Khalis, in Iraq’s Diyala province, after government forces retook the area from the Islamic State group’s control.   (Ahmad Al-Rubaye / AFP/Getty Images)

A Yazidi fighter protects the Sharaf al-Deen temple shrine, one of the holiest for the Yazidis, a religious minority whom the Islamic State group considers heretics deserving to die, in Sinjar, northern Iraq.   (Seivan Selim / Associated Press)

A Free Syrian Army fighter from Shams al-Shamal heads to the front line in Kobani, Syria. Kurdish fighters in Syria have ambitions to become the chief force fighting Islamic State extremists in the country - building on their victory in Kobani to ally with moderate rebels and push the jihadis ever farther.   (Jake Simkin / Associated Press)

Shiite volunteers receive martial arts training at a military base in Najaf, southern Iraq. Shiite volunteers have been assisting the Iraqi army as it battles fighters from the group calling itself the Islamic State.  (Khider Abbas / EPA)

Iraqi Shiite fighters celebrate on February 2, 2015 in al-Mansuriya, in Iraq’s Diyala province, after government forces retook the area from Islamic State group’s control.   (AHMAD AL-RUBAYE / AFP/Getty Images)

Peshmerga fighters take aim at Islamic State militants near Mosul, Iraq last month.  (Anadolu Agency / Getty Images)

A Jordanian child holds a poster of pilot Lt. Moaz Kasasbeh, who was captured by Islamic State militants in Syria and has reportedly been killed.   (Nasser Nasser / Associated Press)

Junko Ishido, mother of Kenji Goto, a Japanese hostage held by Islamic State militants, appears at a Tokyo news conference to appeal to Japan’s prime minister to intervene on her son’s behalf.   (Shizuo Kambayashi / Associated Press )

A video purportedly released by Islamic State on Jan. 20 shows Japanese hostages Kenji Goto, left, and Haruna Yukawa with a militant at an undisclosed location.   (AFP/Getty Images)

A man comforts the wife of captive Jordanian pilot Lt. Moaz Kasasbeh during a protest in Amman, Jordan, on Wednesday.   (Raad Adayleh / Associated Press)

Japanese hostage Kenji Goto holds what appears to be a photo of Jordanian pilot Lt. Moaz Kasasbeh in a YouTube video projected on a big screen TV on Wednesday. The Islamic State hostage has reportedly been beheaded by his captors.   (Eugene Hoshiko / Associated Press)

A picture of a slain fighter with the People’s Protection Units is shown during a celebration the Kurdish victory in Kobani, Syria.  (Ilyas Akengin / AFP/Getty Images)

Kurdish fighters take up positions on Nov. 1, 2014, in an attempt to lure Islamic State militants to reveal their location in Kobani, Syria.  (Jake Simkin / Associated Press)

Iraqi municipal workers remove debris from the scene of a car bombing in central Baghdad on Nov. 9, one of a string of attacks targeting mainly Shiite areas of the capital that has been linked to ongoing fighting between the government and Islamic State militants.  (Ali Abbas / EPA)

A man uses binoculars to watch fighting in the Syrian town of Kobani from a hilltop on the Turkish-Syrian border on Nov. 8.  (Vadim Ghirda / Associated Press)

A mourner flashes a victory sign at the funeral of 19-year-old Syrian Kurdish fighter Perwin Mustafa Dihap, who died Nov. 7 of injuries sustained in fighting with Islamic State militants in her home town of Kobani.   (Vadim Ghirda / Associated Press)

Shiite Muslim pro-government forces drive near the Iraqi town of Jurf al-Sakhr on Oct. 30, after retaking the area from Islamic State militants  (Haidar Hamdani / AFP/Getty Images)

An explosion follows an airstrike in the Syrian town of Kobani on Oct. 28.  (Kutluhan Cucel / Getty Images)

Ethnic Kurds in Turkey greet convoys of fighters from Iraq at the Habur border crossing on Oct. 29. The fighters were on their way to join militias defending the Syrian border town of Kobani from the Islamic State group.  (Ilyas Akengin / AFP/Getty Images)

An Iraqi Kurdish fighter flashes a victory sign as a convoy arrives at the Habur crossing into Turkey on Oct. 29. The heavily-armed fighters were on their way to join militias defending the Syrian border town of Kobani from Islamic State militants.   (Ilyas Akengin / AFP/Getty Images)

Mourners carry the coffin of a Kurdish fighter killed in the battle with Islamic State militants in Kobani, Syria, during a funeral Oct. 21 in Suruc, Turkey, just across the border.   (Gokhan Sahin / Getty Images)

Islamic State militants patrol Oct. 23 near a flag they planted in Syria, just across the Turkish border.  (Bulent Kilic / AFP/Getty Images)

Kurds in Suruc, Turkey, mourn Oct. 23 at the funerals for three Kurdish fighters who died in Kobani, Syria.   (Bulent Kilic / AFP/Getty Images)

A man watches the Syrian town of Kobani through a sniper rifle sight near the Mursitpinar border crossing in Turkey.   (Gokhan Sahin / Getty Images)

An explosion from an airstrike rocks a Syrian hill near Kobani on Oct. 23.   (Bulent Kilic / AFP/Getty Images)

A U.S.-led coalition aircraft flies over Kobani, Syria.  (Gokhan Sahin / Getty Images)

An explosion rocks the Syrian city of Kobani during a reported suicide car bombing by the militant group Islamic State.   (Gokhan Sahin / Getty Images)

Tanks from the Turkish armed forces are dispatched to the border with Syria as clashes intensify between ethnic Kurdish fighters and Islamic State militants on Sept. 29.  (Carsten Koall / Getty Images)

An antiwar protester holds a placard outside the British Parliament, where lawmakers approved plans to join U.S.-led airstrikes in Iraq on Sept. 26.  (Justin Tallis / AFP/Getty Images)

Turkish and Syrian Kurds try to tear down a border fence during protests against the extremist group Islamic State on Sept. 16. Refugees fleeing the militants have flooded into Turkey from Syria.  (Bulent Kilic / AFP/Getty Images)

Shiite Muslim volunteers from the Iraqi city of Tal Afar train at a military camp in Karbala on Sept. 25.  (Mohammed Sawaf / AFP/ Getty Images)

Syrians check a damaged house, reportedly hit by U.S.-led coalition airstrikes, in the village of Kfar Derian in the western Aleppo province on Sept. 23.  (Sami Ali / AFP/Getty Images)

A propaganda video posted on an Islamic State site is said to show recruits marching in an unknown location.   ( AFP /Getty Images)

A video posted on an Islamic State site is said to show recruits training at an unknown location.   (AFP /Getty Images)

Syrian children hold up debris from a damaged house, reportedly hit by U.S.-led coalition airstrikes, in the village of Kfar Derian in the western Aleppo province.   (Sami Ali / AFP/Getty Images)

Lt. Gen. William C. Mayville Jr., director of operations for the Joint Chiefs of Staff, speaks about airstrikes in Syria during a briefing at the Pentagon.  (Brendan Smialowski / AFP/Getty Images)

President Obama, accompanied by Secretary of State John F. Kerry, national security advisor Susan Rice, right, and U.S. Ambassador to the U.N. Samantha Power, meets with the representatives of Bahrain, Qatar, Saudi Arabia, Jordan, United Arab Emirates and Iraq, in New York. Obama met with the five Arab nations that participated in strikes against Islamic State targets in Syria.  (Pablo Martinez Monsivais / Associated Press)

An Iraqi Kurdish Peshmerga fighter fires at Islamic State militant positions from the top of Mount Zardak, a strategic point about 15 miles east of Mosul.  (JM Lopez / AFP/Getty Images)

Kurdish Peshmerga fighters take position near the militant-held city of Zumar in Iraq’s Mosul province on Sept. 4. Iraqi security forces, bolstered by thousands of Shiite Muslim militiamen and ethnic Kurdish fighters, have clawed back ground northeast of Baghdad.   (Ali Al-Saadi / AFP/Getty Images)