ISLAMABAD - The problem of illegal immigrants might confront the Government as one of the most serious challenges under the prevailing security situation. Apart from Afghans, hundreds of thousands of immigrants from other origins are unlawfully sheltering in Pakistan as well. Although there is no specific data that could ascertain the exact number of illegal immigrants of different nationalities residing in Pakistan, yet information provided by different sources indicate that around 500,000 to 800,000 illegal foreigners hailing from Iran, Iraq, Burma, Nigera, Somalia, Jordan, Central Asia, Africa and Middle East origin are dwelling in different parts of Pakistan, besides the illegal Afghan nationals which are 3.5 million in number. Most of the illegal expatriates were those who intended to use Pakistan as a transit state in order to move to United States and Europe. Interior officials confided that thousands of nationals from Iran, Iraq and Central Asia had sought political asylum in Pakistan by showing themselves as refugees. Most of the illegal immigrants from Burma, Uzbekistan, Tajikistan, Turkmenistan, Kyrgyzistan and Azerbaijan had either hidden or lost their passports in order to get Pakistani passports and identity cards. Interior officials mention that Central Asians and Burma nationals mostly apply for Pakistani passports and introduce themselves as Pakistani-based Pathans living in other countries who came to Pakistan to spend vacations and lost their credentials here. While Somalis and Nigerians could be easily identified as Africans, Central Asians have mingled with the locals due to their proficiency in Urdu and other regional languages and facial resemblances. The fact that illegal immigrants in such a huge number managed to enter Pakistan is highly questionable, but government officials say it was Afghan Jihad during the Soviet era which saw the maximum influx of illegal expatriates from African, Middle East and Central Asian countries into Pakistan under the garb of Mujahideen. Thousands of Nigerians and Somalis are into drugs smuggling while hundreds of immigrants from Central Asian states are involved in human trafficking, prostitution, and other heinous crimes. Maximum number of Afghans, Iranians and Central Asians who were living in Pakistan on political asylum were able to get American and European visas. Most of the Iranians, Asians and Afghans are still residing in Pakistan with the hope that they would get US or European visas as refugees. Apart from that, around 200,000 illegal Afghans are residing across Sindh, 500,000 in Punjab, 800,000 in Balochistan and 200,0000 in NWFP with the total number of illegal Afghans being 3,500,000 approximately. On a rough estimate, 4 million to 4.2 million illegal expatriates are living in Pakistan including Afghans and other nationalities.