KABUL (Agencies) - Afghanistan's government on Tuesday said a "foreign intelligence agency" was behind an April 27 assassination attempt on President Hamid Karzai during a military parade in Kabul. The spokesman threatened that Kabul would take action if Islamabad fails to stop militants targeting the war-torn country from across the border. "Evidence shows the hallmark of a particular foreign intelligence agency, which we believe was behind this attack," Karzai's spokesman Homayun Hamidzada said, citing an investigation into the incident. "We cannot provide further details at this time as the investigation continues," the spokesman told reporters, refusing to name the foreign country or the spy organisation. Afghan officials including Karzai have in the past accused Pakistan's intelligence agency of supporting Taliban militants who are waging a bloody insurgency against the Kabul administration. Karzai's spokesman further said Pakistan must stop militants crossing the border to attack targets in Afghanistan, otherwise the Kabul government will take action. "Karzai's comments clarify the fact that terrorism in Afghanistan has external roots and terrorist groups exploiting Pakistan territory attack Afghan military and non-military installations," Homayun Hamidzada told a news conference. "We request Pakistan not to allow terrorist groups to use its soil against Afghanistan, otherwise Afghanistan is obliged to take action in order to defend its nation and people," he said. "All the evidence indicates Afghanistan is being interfered with and the challenges are very great because foreign countries and their intelligence departments support the terrorist groups," Hamidzada said. "Taking advantage of Pakistani soil, they (militants) cross the border and attack military and civilian targets in Afghanistan," Hamidzada said.