Pakistani intelligence has directed law enforcement agencies to step up security across Punjab province to avert possible attacks by militants in retaliation of increased US drone strikes in Wazirsitan tribal belt. <br/><br/>Geo News Channel quoting unnamed sources said, at least four Arab and Uzbek terrorists have been sent to Punjab to carry out attacks and trigger riots and panic in the province.<br/><br/>Punjab's Home Department has directed law enforcement agencies, including police and paramilitary Pakistan Rangers, to make foolproof security arrangements to thwart any possible attack. The home department also fears that the terrorists might target oil depots and key bridges in the province. <br/><br/>Law enforcement agencies were alerted that the terrorists might use explosive devices made with fertilizers, oil and ball bearings or explosives-laden cycles and cars for their attacks.