Reply To: Rav Elyashev Bans Nachal Chareidi

sam2: Igros Moshe EH 4:60 famously writes that even talking to a girl on the phone is an Issur d’Oraisa of Lo Sikrvu and Yeiharei v’al Ya’avor. See also Gemara Sanhedrin 75a, Rema YD 157:1, Chavos Yair 182, Sidrei Tahara on YD 195:15 and Gra there