Dhaka: Bangladesh on Sunday mourned the victims of the horrific terrorist attack on a Dhaka cafe that left 22 persons, dominantly foreigners including an Indian, dead and the nation traumatized. The national flag flew at half-mast as a two-day mourning declared by the government began. People would wear black badges and prayers would be offered in mosques, temples and other places of worship, the Daily Star reported. At least seven Islamists said to be Islamic State militants stormed the popular Spanish Holey Artisan Bakery in Dhaka's diplomatic zone on Friday night, taking more than 30 people hostage. The 20 persons were brutally murdered during the 12-hour siege before Bangladeshi forces stormed the cafe and rescued 13 hostages, including one Japanese and two Sri Lankans. The victims include 10 males and 10 females, Xinhua news agency quoted an unnamed official as saying. Six terrorists were killed in the 50-minute army-led "Operation Thunderbolt". A seventh attacker was captured alive. All the attackers were Bangladeshis and five of them were wanted by police. Inspector General of Police Shahidul Hoque told CNN that police had previously tried to arrest the five. The Islamic State claimed responsibility for the attack, saying its gunmen "killed 24 persons and injured more than 40 in the attack at a cafe in Dhaka". Two police officials were also killed in gunfire earlier in the standoff, authorities said. The Bangladesh Army said those killed included nine Italians, seven Japanese, an Indian girl, two Bangladeshis and a US citizen of Bangladeshi origin. Bangladesh Prime Minister Sheikh Hasina on Saturday declared a two-day mourning for the victims. Condemning the "extremely heinous act", she vowed to root out terrorism from the country which has seen a spate of deadly attacks by the IS and Al Qaeda-linked militants on academics, writers, activists and religious minorities in the Muslim-majority country. "We'll establish Bangladesh as a peaceful state... No conspiracy can hinder our advancement," she said. "What kind of Muslims are these people? They don't have any religion. People must resist these terrorists. My government is determined to root out terrorism and militancy from Bangladesh," she said. In India, President Pranab Mukherjee, Prime Minister Narendra Modi and West Bengal Chief Minister Mamata Banerjee condemned the attack. Modi telephoned Sheikh Hasina to condemn the "despicable attack" and said India "stands firmly with our sisters and brothers of Bangladesh" in this hour of grief. Indian External Affairs Minister Sushma Swaraj confirmed the killing of 19-year-old Tarishi Jain of Firozabad in Uttar Pradesh. She had passed out from American School Dhaka and was studying at Berkeley. The hostage crisis, the first such incident in Bangladesh, began around 8.30 p.m. on Friday after the attackers carrying firearms, bombs and swords barged into the cafe. The gunmen, shouting "Allahu Akbar", slaughtered those who were unable to recite the Quran, said rescued hostages. The siege ended around 8.30 a.m on Saturday morning. The Italian Foreign Ministry identified the Italian victims as Adele Puglisi, Marco Tondat, Claudia Maria D'antona, Nadia Benedetti, Vincenzo D'allestro, Maria Rivoli, Cristian Rossi, Claudio Cappelli and Simona Monti.