The letter threatened to attack the university with a suicide attack or a series of bombings, according to a police officer. And UET public relations officer Dr Tanvir Qasim confirmed the letter had been received via posted mail from an unidentified source. However, he said the contents of the letter were unknown to him.UET sources claim the letter was received yesterday from unknown sources claiming to be from IS, threatening to attack hotels and the university campus after which security within the UET campus was put on high alert.DIG Lahore Dr Haider Ashraf said security around the university has been increased with increased patrolling and checkpoints.DIG Ashraf also said a search operation will be launched in the UET hostels later today to sweep-check the premises.However, he added that the letter could be a hoax, but this can only be ascertained after an investigation. DIG Ashraf said till then, the threat would be taken seriously.The Civil Lines Police Division has also been asked to remain alert.Ashraf said that they will also launch a search operation in UET hostels later today to sweep check the premises.On the other hand, a police official revealed that the threat letter was a hoax to spread panic in city.In October 2014, a threat letter was handed over to guards of Kinnard College Lahore that later turned out to be a hoax.It also not the first time that Lahore has come under the threat of IS presence. In November last year, Lahore police launched a manhunt to find men who either belonged to IS, or those who aspired to be in IS after pamphlets, posters and stickers of IS were distributed on the boundary wall in parts of the city. The Lahore police then claimed that Lahore was IS-free, however this letter has raised concerns.Further, agencies have issued a list of various universities that are under threat, of which UET, according to sources, is not on that list.