United States has expressed concern over the disappearance of five Pakistani anti-Taliban activists and bloggers who mysteriously went missing last week. State Department spokesman Mark Toner in his press briefing yesterday said, US is very much concerned about the reported missing and Washington will continue to monitor the situation in Pakistan.<br/><br/>Pakistan's Human rights activist Syed Talib Abbas has criticized the Pakistan Government over its inaction against militants. He said none of the men have been found so far. Meanwhile, Pakistan's Interior Ministry said, it had asked police to step up efforts to find the missing men, who include Salman Haider, a university professor and rights activist.<br/><br/>No militant group has so far claimed abducting the activists and no Government department or intelligence agency has said it detained or arrested any one of the five.