A German woman was fatally shot and an Afghan guard was reportedly beheaded at a guesthouse after insurgents stormed the compound. A Finnish woman was also missing and possibly kidnapped after the attack late Saturday in Kabul, police said.

No group has asserted responsibility, but security officials and foreign embassies have been warning that either the Afghan Taliban or foreign-linked Islamic State militias would probably stage high-profile attacks in the capital as the holy month of Ramadan is set to begin this week.

The guard at the guesthouse, which is run by a Swedish aid group, was reportedly beheaded, a method often used by the Islamic State and generally not practiced by the Taliban. Then, according to a spokesman for the Interior Ministry on Sunday, the attackers went to a second-floor room where the two women were asleep, shot one dead and abducted the other.

The victims’ names were not immediately made public. None of the assailants were caught.

Security officials said two additional foreign women in the house were unharmed and that an intensive investigation was underway to find the assailants. The Finnish Embassy confirmed that a Finnish citizen was missing.

[Islamic State targets NATO convoy in Kabul]

The guesthouse is operated by Operation Mercy, a Swedish aid and development charity, and all of its foreign employees are believed to stay there. The local director of the group, Scott Breslin, told news services that the organization was holding a crisis meeting, but he gave no details about the attack or the victims.

Police and neighbors said five foreigners lived in the guesthouse, dressed in modest Afghan clothing and spoke the Afghan Dari language. There was some local speculation that they were Christian missionaries, but people familiar with the group described it as faith-based but not missionary.

Several missionary-run charities have operated quietly in Kabul for years but remain targets for Islamist extremist groups.

Operation Mercy’s website says that the group operates in Central Asia, the Middle East and North Africa in projects that include aiding women and children. It lists prayer as one of its priorities to seek “God’s presence, blessing and involvement in our lives and work” but does not cite any specific faith.

The guesthouse and office of Operation Mercy are located in a rapidly developing section of Kabul that includes the new parliament, the American University, several newly built ministries and the home of President Ashraf Ghani.

[Return of warlord Hekmatyar adds to Afghan political tensions]

In a separate attack Sunday morning, two Afghan employees of the Anti-Corruption Justice Center, an agency that works with the attorney general’s office, were fatally shot on their way to work, police said. Officials have been expecting threats and attacks on police, courts and prisons during this period.

The last major insurgent attack in Kabul came on March 8, when Islamic State militants disguised as medical workers invaded a large military hospital and fatally shot more than 30 patients, staff members and visitors.

In the past week, Islamic State gunmen and suicide bombers attacked a government media compound in eastern Jalalabad city, and Taliban fighters struck a bank in the southern city of Gardez.

Sunday’s incident was the first attack against foreigners in the capital in recent months, but it followed a number of similar incidents in the past several years.

In August, two foreign faculty members at the nearby American University of Afghanistan, one American and one Australian, were kidnapped from their vehicle just outside the university gates. Their whereabouts are still unknown, but they appeared in a Taliban video in January that included a demand for ransom.

A number of foreign charity and development workers have been abducted in Afghanistan over the years, and several have been released after ransom was paid. Kidnappings are often carried out by criminal gangs that sometimes turn their captives over to the Taliban.

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