NEW DELHI: A Swedish couple had the police show up at their doorstep when passerby’s mistook birthday balloons indicating the number “21” -- a 21st birthday party -- for “IS”, the abbreviation for the Islamic State.

The balloons were for Sarah Ericsson's birthday party that was held at her boyfriend’s, Fabian Akesson's, home. Akesson was reportedly brushing his teeth when the police arrived. “laughed about it and even showed them a picture that we took. And from that perspective, it looked almost like the letters 'IS',” Akesson was quoted by the media saying.

Ericsson, who was in class at the Blekinge Institute of Technology told the “Local” that “It [the incident] was a little strange.” “We understand why someone would report it if they thought it looked like IS-propaganda, although everyone else just thought it looked like the number '12' from outside,” the birthday girl said.

The police called for the balloons to be taken down, and Ericsson and Akesson were quick to comply. “Extremism should always be taken seriously, and we did take the balloons down immediately,” Ericsson told the local.

Meanwhile, the Islamic State abducted at least 150 people from Assyrian Christian villages in northeastern Syria. "We have verified at least 150 people who have been abducted from sources on the ground," Bassam Ishak, President of the Syrian National Council of Syria, told Reuters.

The news follows a statement by the Syrian Observatory of Human Rights that said that at least 90 were abducted when the militants carried out raids on rural villages home to the ancient Christian minority west of Hasaka, a city mainly held by the Kurds. The Islamic State operated radio channel, al-Bayan, seemed to confirm the abductions as it reported that the militants had seized "tens of Crusaders.”

According to reports, the militants have taken male captives to nearby Abdul Aziz mountain and is holding women in the village of Tal Shamran -- where rights groups say most of the captives came from. Several thousand people are believed to have fled the villages on the north bank, with an estimated 3000 heading for Hassakeh and Qamishli.

The abductions happened as Syrian Kurdish fighters backed by US-led air strikes advance into Islamic State-held territory in the country’s northeast. On Sunday, Kurdish Peshmerga forces and the People's Protection Units (YPG), backed by US-led coalition aircraft, launched an offensive in the area, seizing 20 Islamic State-held villages on Sunday itself and another 10 on Tuesday.

Elsewhere, in Iraq, the group reportedly destroyed the Mosul Public Library, that contained 8000 rare books and manuscripts. “ISIS militants bombed the Mosul Public Library. They used improvised explosive devices,” said Ghanim al-Ta'an, the director of the library, told the media. The manuscripts dated to the eighteenth century and the library housed books printed in Iraq's first printing house in the nineteenth century. It also had collections from the Ottoman era, Iraq’s first few newspaper editions, and antiques used by the Ancient arabs. It also housed the personal collections of more than 100 notable families from Mosul.

The group also reportedly destroyed the Church of Mary the Virgin in Mosul and attacked the Mosul University Theater. In December last year, the militants had burnt Mosul University’s central library.