New Delhi, Aug 27 : Pro-Khalistan graffiti appeared at various metro stations in the national capital on Sunday following which the Delhi Police has lodged an FIR against unknown persons. The graffiti appeared at more than seven stations and near a government school as well. The police have removed all the graffiti ahead of the G20 Summit in the national capital. The derogatory graffiti slogans challenging the sovereignty of India appeared at following metro stations: ShivaJi Park, MadiPur, Paschim Vihar, Udyog Nagar, and Maharaja Surajmal Stadium; Punjabi Bagh and Nangloi Metro Stations. Graffiti had also appeared at government Sarvodya Bal Vidyalya Nangloi. A police source said that pro-Khalistani supporters may be behind these graffiti. Name of Sikh for Justice (SFJ) was also mentioned in graffiti. 'Modi India's committed genocide of Sikhs, Khalistan Referundum Jindabad, Delhi Banega Khalistan etc were written,' the police said. The police said that they are examining the CCTV footage from nearby areas and metro stations to identify the culprits. The police said that it also lodged an FIR against unknown persons and investigation is underway. /IANS