Pakistani Prime Minister Yousuf Raza Gilani on Friday demanded that NATO forces in Afghanistan pay compensation or apologise for recent cross-border attacks, warning that his country would otherwise explore "other options" to stop such border violations.
Two helicopters entered Pakistani airspace on Thursday and fired missiles at a border post manned by six soldiers, killing three of them and injuring the others.
"If you (NATO) do not explain the incident and if you do not pay compensation or apologize, then we have other options and we will use them," Gilani told parliament.
"Being a responsible nation we have conveyed our response through diplomatic and political means, but I assure the nation through this house that we will not allow any incursion into Pakistan," he said.
It was the third cross-border incursion by international troops this month.
Hours after the attack Pakistan stopped dozens of trucks and oil tankers carrying food and oil supplies to NATO troops in Afghanistan.
The international forces are highly dependent on Pakistan for supplies, as around 80 per cent pass through Pakistan to reach landlocked Afghanistan.
Pakistan is a major ally of the US-led forces in the fight against the Taliban-led insurgency.
But analysts suspect Pakistan's Inter-Services Intelligence (ISI) agency is playing a double game by allowing the militants to sneak into Afghanistan.
Western forces have long demanded to use the right of "hot pursuit" against insurgents who return to Pakistani tribal areas after attacks in Afghanistan.
Pakistan has declined, saying the mandate of international troops ends at the border and only Pakistani troops can take action against militants inside its territory.