Fighting along the border between Pakistan and Afghanistan lasted about 2 hours Monday. There were no casualties reported.
Pakistani Foreign Ministry spokesman Aizaz Ahmad Chaudhry told Radio Free Europe/Radio Liberty's bureau in Pakistan that Afghan forces fired the first shot.
"Military-to-military contact has been established and we are trying to resolve (the issue)," he said.
The Afghan government said the Pakistanis shot across the border first. Afghan President Hamid Karzai last weekend said Pakistan was trying to provoke a fight to pressure his administration to accept borders drawn up in the 19th century. Karzai said he would "never recognize" that border.
Afghan security forces are gearing up for the 2014 departure of international forces. The security situation is tense in Pakistan as the country prepares for elections later in May.
The United Nations estimates more than 70,000 people have been displaced on the Pakistani side of the border because of internal fighting.