PESHAWAR- Border clashes between Pakistani and Afghan security forces broke out today, officials said, killing at least one person and potentially undermining efforts by both sides to improve relations.

One Afghan border policeman was killed in the fighting near the border town of Angoor Adda, Afghan Ministry of Interior spokesman Sediq Sediqqi said in Kabul.

Pakistan's military said two troops were injured and none were killed.

Afghan President Ashraf Ghani has tried to improve relations with his nuclear-armed neighbor to the east, saying unless the two sides work together, they will never end the war with Taliban insurgents who threaten both countries.

His overtures have drawn criticism among Afghan critics, and border clashes such as the one on Wednesday threaten to raise tensions.

Afghan spokesman Sediqqi indicated that the fighting started when Pakistan attempted to build an illegal structure on the border.

"Afghan border police intervened and exchanged fire. As a result, one Afghan border policeman was killed," he said.

The Pakistani military said in a statement that the clashes were touched off by Afghan firing.

"An RPG-7 rocket and few rounds of small arms were fired on Angoor Adda gate from the Afghan side, due to which two Pakistani security personnel were injured," it said, adding that Pakistani troops then returned fire.

Local resident Sahib Noor said by telephone from the Pakistani side that the border was sealed on Wednesday and no one was allowed to cross.

Another resident, Khan Wazir, said Pakistani and Afghan forces were still facing off from positions along the border at the end of the day.