Concerned over increasing number of Pakistani-origin citizens living in the West being attracted to terrorism, the Government is contemplating to tighten the visa approval norms for such persons visiting India. Home Ministry sources said, the government is particularly concerned over the recent reports of five young Americans, two of them of Pakistani-origin, arrested in Pakistan for links with Al-Qaeda.The arrests came in the wake of busting of the Lashker-e-Taiba plot, in which the Pakistan-based terror group was planning to use David Coleman Headley, to launch terror attacks in India. Pakistani-Canadian Tahawwur Hussain Rana, an aide of Headley, was also arrested for his links with terror groups. The sources said, these are disturbing reports as India is always a<br/>prime target of terrorists. The Government has to think ways which can effectively deal with such a sensitive issue.Among the steps that are being mulled by the government include making it mandatory for visa applications of Pakistan-born citizens of any country to be cleared in New Delhi, fixing number of visits in a year and having reference letters from past travellers.