Two persons moving around in a suspicious manner near a key ISRO facility on the outskirts of Bangalore fired at security personnel in the wee hours today after which the guards retaliated but the duo escaped. <br/>ISRO sources said the security personnel challenged the two when they found them moving around in a suspiciousmanner. ISRO spokesperson, S Satish, told PTI that Security was in place and the attempt to attack the guards was foiled. He said investigations are on. his ISRO facility houses the Indian Deep Space Network and tracking station for ISRO's satellite missions.