In a second such attack within the past three days, militants hurled a grenade on a police station at Lal Bazar on the outskirts of the city, official sources said on Sunday. However, no one was hurt in the blast last night as the explosive device fell short of the target and exploded outside the boundary wall of the police station, the sources said. On Friday, militants carried out a grenade attack on a police station at Baramulla district headquarters, injuring 13 security personnel -- seven CRPF and six police personnel.  No militant outfit has so far claimed responsibility for the attacks, viewed as part of the nefarious designs of militants to step up violence ahead of the upcoming seven-phased assembly elections in Jammu and Kashmir beginning November 17. Police assisted by CRPF personnel carried out searches in the close vicinity of the police station at Lal Bazar immediately after the grenade attack around 9 PM, but no one was arrested, the sources said.  The sources said the militants had apparently fled the scene taking advantage of darkness. Authorities have made elaborate security arrangements across the militancy-hit border state to ensure peaceful polls.