The Interior Ministry has directed the law enforcement agencies to tighten the security across the country here on Friday. Government has received some reports about the suicide bombers being sent from Swat and tribal areas in various parts of the country, the interior ministry said. The suicide bombers could target the security forces and important places in Rawalpindi, Karachi and Lahore, the sources said. According to the sources Law enforcement agencies have been informed that terrorists were aware of the security measures taken by the government.