A civil defense worker carries a child after a reported government airstrike in the northern city of Aleppo, on Jan. 16, 2016, as regime forces battled the Islamic State in Aleppo province. (Karam Al-Masri/AFP/Getty Images)

The Islamic State is intensifying a brutal siege against President Bashar al-Assad’s last stronghold in eastern Syria in an apparent show of strength as the group suffers battlefield defeats elsewhere.

The extremist organization has unleashed waves of suicide bombers and other attacks in the push to seize government-held areas in the city of Deir al-Zour, according to monitoring groups. An estimated 200,000 people in those areas are running out of food and medicine after a year-long blockade by the group, with the United Nations expressing concern about possible deaths due to starvation.

The city’s fall would mark an effective end to the Assad government’s control of the vast expanses of eastern Syria, an area that is now mostly divided between Kurdish forces and the Islamic State. It would also
deal a symbolic but important blow to Russia’s military campaign in Syria, which has helped Assad’s forces regain momentum against rebels in the western part of the country.

Moscow says it intends to cripple the Islamic State, but the United States and Syrian opposition figures say Russian airstrikes have mostly targeted other groups opposed to Assad’s rule.

The Islamic State’s escalating attacks on Deir al-Zour are “about reversing setbacks” in parts of Syria and Iraq where the group has been losing territory to U.S.-backed opponents, said Emile Hokayem, a Middle East analyst at the London-based International Institute for Strategic Studies.

Deir al-Zour, once a sleepy farming town known for scenic views of the Euphrates River, is the capital of an oil-producing province of the same name. Most of the province has fallen to Islamic State control.

In recent months, Kurdish forces in Syria have seized vast tracts of land from the extremist group just north of Raqqa, the capital of its self-declared caliphate. The country’s ethnic Kurds, who have fought intense ground battles against the Islamic State, are exploiting the chaos of war to carve out an autonomous enclave in the northeast.

Last month, Iraqi forces drove Islamic State militants out of the city of Ramadi, dealing another blow to the militant group in Iraq.

A U.S.-led coalition has conducted airstrikes to help the anti-Islamic State forces in both countries.

The Islamic State has for a year encircled and gradually taken control of Deir al-Zour, about 280 miles east of the capital, Damascus.

Nelly Lahoud, an expert on political Islam at the International Institute for Strategic Studies, said that “news of ISIS seeking to expand its territory serves as a morale boost for its fighters. It’s as if they are resuming their conquest phase, a break from their recent contracting phase.” The Islamic State is also known as ISIS and ISIL.

The group’s attacks against government defenses in the city have become especially brutal in recent weeks, according to monitoring groups and government media. They have reported a massacre, mass kidnappings and waves of suicide attacks, including against a government air base in the area.

Activists from the city, however, say the government has exaggerated those claims.

But the militants appear to have seized a government arms depot in the area that held antitank missiles, artillery and other heavy weapons.

Still, analysts say, losing Deir al-Zour could actually benefit Assad, freeing up resources for the fight in western areas of Syria, which are considered more important to his government’s survival. Those areas include the capital and territory that runs along the Lebanese border and western coastline. And that is where U.S. officials and Syrian opposition figures say Russia has concentrated its air raids, backing a government-led offensive since late September against rebels that oppose the Islamic State.

“I don’t expect the regime to put up a big fight against ISIS in Deir al-Zour,” said Lina Khatib, a Syria analyst at the Arab Reform Initiative. But she said losing the city would undermine Russia’s anti-Islamic State narrative to justify its involvement in the civil war, a conflict that has led to more than 250,000 deaths, displaced millions and empowered extremists. The fall of the city “would certainly reinforce the notion that the Russian campaign in Syria is definitely not aimed at ISIS,” Khatib said.

Still, Moscow says it has stepped up support to its besieged allies in Deir al-Zour, airdropping dozens of tons of humanitarian aid to government-held areas while carrying out airstrikes against Islamic State militants.

On Sunday, the Britain-based Syrian Observatory for Human Rights said at least 63 people, including nine children, had died in airstrikes believed to have been carried out by Russian warplanes near Deir al-Zour, the Reuters news agency reported.

The humanitarian aid is desperately needed, says the United Nations, which has struggled to deliver food and medicine to government-held areas of the city because of the siege.

Water is available once a week for three hours, according to the Office for the Coordination of Humanitarian Affairs. A report by the U.N. agency this month cited severe malnutrition and possible deaths by starvation.

Perhaps just as problematic for trapped residents, activists from the city say, is the extortion imposed by government officials. For instance, they charge as much as $5,000 for evacuation by helicopter, a sum that few can afford, said Karam al-Hamad, an activist from the city who lives in Turkey. Officials also have been seizing humanitarian aid and selling it to desperate residents at exorbitant prices, he said.

“The people are trapped, and the regime is benefiting from the siege,” Hamad said.

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