At least seven security personnel and 16 others were injured in a series of powerful explosions in Srinagar, summer capital of Indian-administered Jammu and Kashmir Monday. Terrorists lobbed a powerful hand grenade at a bunker of the Indian Central Reserve Police Force (CRPF) in downtown Srinagar Monday, news agency Indo-Asian News Service reported. "The grenade exploded near the bunker injuring four paramilitary CRPF troopers and two civilian bystanders. The injured were taken to the hospital for treatment," police told reporters today in Srinagar.The terrorists also attacked the Jammu and Kashmir police in another part of Srinagar with a hand grenade that exploded injuring five people including two police personnel. In another incident terrorists fired a rifle grenade towards a police check-point at Munwar in downtown Srinagar, injuring three policemen and two civilians, the agency reported. Meanwhile, security has been strengthened in Srinagar ahead of the two-day roundtable on Kashmir issue to be chaired by the Indian Prime Minister beginning May 24. Four guerrilla groups have threatened to disrupt the roundtable.