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KABUL, Afghanistan — Gunmen stormed a religious gathering of Afghanistan's minority Sikhs in their place of worship in the heart of Kabul's old city on Wednesday, killing at least four people, a Sikh lawmaker said.

Within hours, the Islamic State group claimed responsibility for the attack. Those killed included a child whose body was brought to a Kabul hospital, the emergency services and the hospital said. At least 15 people were wounded.

Afghanistan's Interior Ministry said police responded promptly to the attack on the Sikh place of worship, known as a Gurdwara, with shooting still underway.

The lawmaker, Narindra Singh Khalsa, said he rushed over to help after receiving a call from a worshipper inside the Gurdwara telling him of the attack. There were about 150 worshippers inside the Gurdwara at the time of the attack, he added.

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Several of the worshippers were being held hostage by the gunmen who were lobbing grenades at the Afghan special forces, Khalsa said, but added he couldn't say how many were being held.

Afghan security forces inspect near the site of an attack in Kabul, Afghanistan , on Wednesday. Mohammad Ismail / Reuters

The Interior Ministry said the first floor of the Gurdwara had been cleared but that Afghan special forces, aided by international troops, were moving slowly throughout the remainder of the building.

The SITE Intelligence Group, which tracks militant postings and groups, said IS claimed responsibility for the attack on the group's Aamaq media arm.

At a Kabul hospital, Mohan Singh, who was in the Gurdwara when the attack began, said he first heard the sound of gunshots and ran for cover under a table. Later he heard the sounds of explosions, adding that he believes they were hand grenades. He was injured when parts of the ceiling fell on him.

In photographs shared by the Interior Ministry, about a dozen children were seen being rushed out of the Gurdwara by Afghan special forces, many of them barefoot and crying.

Earlier, as the news of the attack broke, Taliban spokesman Zabihullah Mujahed tweeted that the Taliban were not involved. Earlier this month, Afghanistan's IS affiliate struck a gathering of minority Shiite Muslims in Kabul, killing 32 people.

Sikhs have suffered widespread discrimination in the conservative Muslim country and have also been targeted by Islamic extremists. Under Taliban rule in the late 1990s, they were asked to identify themselves by wearing yellow armbands, but the rule was not enforced. In recent years, large numbers of Sikhs and Hindus have sought asylum in India, which has a Hindu majority and a large Sikh population.

In July 2018, a convoy of Sikhs and Hindus was attacked by an Islamic State suicide bomber as they were on their way to meet Afghan President Ashraf Ghani in the eastern city of Jalalabad, the capital of Nangarhar province. Nineteen people were killed in that attack.