Islamabad: A Pakistani court on Monday dismissed the case against an American FBI agent arrested for trying to board a plane while carrying ammunition, officials said.
The unidentified agent was held at Karachi airport early this month when security staff found him carrying 15 rounds for a 9mm handgun during routine checks before a flight to the capital Islamabad.
The Federal Bureau of Investigation agent was later released on bail. The Washington Post has said he was on temporary assignment in Pakistan to help local authorities investigate corruption.
A district judge in Karachi, Hasan Ali Kalwar, quashed the case after police failed to present any evidence against the agent.
The judge said police had invoked an incorrect section of the law.
"He was not carrying any weapon but was carrying only the bullets and magazines," Kalwar was quoted as saying by a court official.
Police did not pursue the case after the interior ministry informed them that the agent was authorised to carry the ammunition, police officer Khalid Mehmood told AFP.
The agent`s lawyer also submitted a copy of a US embassy letter showing that he was on a mission and was allowed to carry the ammunition.
The incident came at a time of relative tranquillity in Washington`s often-fraught relationship with Islamabad.
Ties have improved markedly since almost collapsing in 2011 amid a series of crises, including the US raid in Pakistan that killed Al-Qaeda chief Osama bin Laden -- which Islamabad branded a violation of sovereignty.
The fatal shooting of two men by CIA contractor Raymond Davis in the eastern city of Lahore in January 2011 also sparked a diplomatic crisis between the two "war on terror" allies.
A Pakistani court eventually freed Davis following the payment of $2 million in blood money to the families of the dead men.