KABUL—Islamic State fighters disguised as doctors fought elite government forces inside Afghanistan’s largest military hospital on Wednesday in a seven-hour battle that left at least 30 people dead and 50 others wounded, Afghan officials said.

Islamic State’s regional affiliate, Khorasan Province, said it carried out the attack, which began when a suicide bomber detonated a car bomb at the entrance of the heavily guarded medical facility in the Afghan capital. In a statement, Khorasan Province said four of its fighters armed with suicide vests then entered the compound.

As the gunmen and security forces exchanged fire inside the complex, hospital personnel scurried to protect patients and evacuate them to safety. Among those killed were an unknown number of doctors, the Afghan defense ministry said.

A photo distributed by Islamic State’s official Amaq news agency purportedly taken inside the besieged hospital showed what it said was a militant posing next to an automatic rifle, wearing a surgical mask and holding a dagger. Another photo showed the bodies of unidentified victims. All the gunmen died in the fighting, Afghan officials said.

The assault on the U.S.-funded Dawood National Hospital, along with the expected start soon of the Taliban’s spring offensive, could increase pressure on the Trump administration to deploy more troops to Afghanistan.

In testimony to U.S. Congress last month, Army Gen. John Nicholson, commander of U.S. and international troops in Afghanistan, said more coalition troops were needed in the country to end what he described as a stalemate in the 16-year-old war.

Wednesday’s attack wasn’t the first on Dawood National Hospital. The facility, which is operated by the Afghan army and treats only members of the country’s security forces and their relatives, was hit in 2011 by the Taliban, Afghanistan’s largest insurgency, an assault that left six people dead.

The Taliban denied any involvement in the latest attack on the hospital. Dawlat Waziri, a defense ministry spokesman, said it didn’t matter which of the two groups were responsible.

“They are both enemies of the people and of this country,” he said. “We will eliminate them.”

The assault on the hospital reflects the growing strength of Khorasan Province, Islamic State’s regional branch. Aided by their disguises, the attackers succeed in penetrating the thick security cordon around the highly fortified hospital compound, which is located in the heart of Kabul near embassies and military installations.

Since emerging in 2014, Khorasan Province has operated mainly in eastern Afghanistan and in small areas of western Pakistan. Recently, it has shifted its focus and carried out high-profile attacks in Kabul, adopting tactics long used by the Taliban.

Last month, an Islamic State fighter detonated his suicide vest at the gates of Afghanistan’s Supreme Court, killing 21 people and wounding 41 others. The group said the bombing was aimed at judges and their staff, according to a statement carried by SITE Intelligence Group, which monitors global jihadist activity.

Islamic State also frequently targets Afghanistan’s minority Shiites, whom it considers apostates. In the most recent attack, a suicide bomber killed about 30 worshipers in a Shiite mosque in Kabul.

The assault on Wednesday is the latest by armed groups in the capital, as government forces continue to suffer high casualties as they struggle to maintain security.

The Taliban carried out attacks against two Afghan security compounds last week, killing 21 people. Among the dead were Afghan civilians, who have become increasingly victimized by the fighting.

In a report issued in February, the United Nations said more than 11,400 civilians were either killed or injured last year, the highest number since the organization began gathering data eight years ago.

The U.S.-led international military coalition condemned Wednesday’s attack on the hospital, which was the focus of a U.S. congressional investigation following allegations in 2011 of corruption and patient neglect.

“Once again insurgents show complete disrespect for humanity by attacking a hospital. We stand with Afghan people against terrorism,” the coalition said on Twitter.