Russian-speaking militants from a Chechen-led faction within the Islamic State (IS) group are involved in IS's assault on Iraq's largest oil refinery.
IS launched suicide attacks on the perimeter of the Baiji oil refinery, an important strategic resource 200 kilometers north of Baghdad in Iraq's Salahuddin Province, on April 11.
An Iraqi officer from Salahuddin told CNN on April 12 that the militants had attacked the complex on three fronts to the south, the west, and the east.
The militants have been able to take control of parts of the refinery including a distribution point and storage tanks, although a source in the Salahuddin military operations command told Reuters on April 16 that IS has not been able to take any major infrastructure.
Evidence that the Chechen-led IS group Katibat Al-Aqsa (KAA), which has previously fought predominantly in Syria, is participating in the fighting at Baiji emerged on April 16, when Russian-speaking IS media activist Murad Ataev announced the death of a prominent KAA militant.
Ataev said that the militant, who was known as Ilyas Deniev or Salakhaddin Shamsky, had been killed in a clash with Iraqi security forces when he was hit by fire from a "Dushka," the Russian nickname for a DShK 1938 heavy machine gun.
Deniev, who has posted photographs of himself together with his baby daughter, was involved with the Sham Today group of media activists who promoted the activities of IS's North Caucasian and other Russian-speaking militants in Syria and Iraq.
Photos of Deniev showing him in Mosul were posted on social media last summer, around the time that IS overran the city, although the photographs did not show Deniev taking part in fighting and it is not clear whether KAA was involved in the Mosul offensive.
A Russian-speaking militant also appeared in a video released by IS on April 16 and which shows the fighting in Baiji. The militant, who appears to be older than his Russian-speaking counterparts in KAA, asks an Arabic-speaking IS militant to say something on his behalf. The Russian-speaking militant has not appeared in any photographs of KAA members posted on social media and it is not clear whether this militant is a member of that group or another faction.
KAA has fought in a number of key IS offensives in Syria -- including against Kurdish militia in Kobani and against Syrian military forces at the Tabqa air base in Raqqa Province in August 2014.
The group has close ties to Umar al-Shishani, the IS military commander in Syria, though evidence has yet to emerge to suggest that Shishani is commanding the group in Baiji.
What the presence of the Chechen-led group at the Baiji offensive does indicate, with or without Shishani, is that IS is sending some of its more experienced fighters to what the militants consider to be an highly strategic battle. IS has also used apparently used drones in the Baiji offensive, as the Long War Journal documented.
The United States also sees Baiji as having high strategic importance, because of its oil infrastructure. Army General Martin Dempsey, chairman of the Joint Chiefs of Staff, said on April 16 that the United States and its allies are concentrating air strikes on Baiji, even as IS militants are close to taking the town of Ramadi in the Anbar Province.
Iraqi Prime Minister Haider al-Abadi said that the IS group wanted to send a message after their loss of the Iraqi city of Tikrit to Iraqi government forces.
"I think it's timed to [coincide with] my visit to the U.S. I think they want to show that despite the support that Iraq is receiving, they are there to cause damage," Abadi said, speaking at the Center for International and Strategic Studies think tank in Washington, D.C.
-- Joanna Paraszczuk