Intelligence shortfalls led to the deaths of 2 hostages

The US drone strike that accidentally killed two hostages in Pakistan exposes intelligence shortfalls that former and current US officials say appear to be growing more frequent as militants expand their safe havens and as Washington gathers less on-the-ground human intelligence.

US President Barack Obama's admission on Thursday that a US drone strike accidentally took the lives of two hostages - one US citizen and one Italian - has raised fresh questions about the limits and the risks of the country's "targeted killing" campaign. The strike also killed two US citizens who had leadership roles with al-Qaida.

Obama said he took full responsibility for the January CIA strikes and regretted the deaths of US doctor Warren Weinstein and Italian aid worker Giovanni Lo Porto. The president cast the incident as a tragic consequence of the special difficulties of the fight against terrorists.