Islamist militants killed 20 people, including at least nine Italians, inside an upmarket restaurant in Bangladesh’s capital, before security forces stormed the building and ended a 12-hour standoff on Saturday.

Islamic State said it was responsible for one of the most brazen attacks in the South Asian nation’s history, but that claim has yet to be confirmed. It marks a major escalation in a campaign by militants over the past 18 months that had targeted mostly individuals advocating a secular or liberal lifestyle in majority-Muslim Bangladesh.

The gunmen, who stormed the busy restaurant in Dhaka’s diplomatic area late on Friday night, ordered all Bangladeshis to stand up before they began killing foreigners, a source briefed on the police investigation said.

Among the dead was the wife of an Italian businessman killed by a machete. She was found by her husband after he spent all night hiding behind a tree outside the cafe while the gunmen were inside, said Agnese Barolo, a friend who lives in Dhaka and spoke to him.

Nine Italians were killed in the attack, the country’s foreign minister said, and authorities were trying to confirm the fate of another person missing.

Seven Japanese citizens were unaccounted for, while one Indian, a 19 year-old female student, was killed in the assault, India’s foreign minister said on Twitter. The killing of foreigners will likely shatter the confidence of the expatriate community in Bangladesh, many of whom work for multinationals in the country’s $26 billion garment industry that accounts for around 15 percent of the economy. Bangladesh is the world’s second largest apparel exporter after China.

Thirteen hostages were rescued, including one Japanese and two Sri Lankans, the army said.

A total of six attackers

were shot dead at the finale when elite commandos stormed the cafe.