KABUL (Reuters) - Afghanistan on Friday complained to Pakistan for a second time in a week about its shelling of Afghan villages in which four children were killed, fighting that threatens to raise regional tensions as the United States begins a gradual troop withdrawal.
The Afghan Ministry of Foreign Affairs first complained on Monday about Pakistan shelling soon after an assault by Pakistani forces drove militants across the border.
The two sides blame each other for failing to crack down hard enough on militants along a porous border across which insurgents move freely.
Islamabad this month also complained twice to Kabul that militants had been attacking Pakistani villages from across the border in Afghanistan.
The Afghan government said that ten Pakistani artillery shells landed in Sarkano district of Kunar province on Thursday night, killing four children, and in Goshta district of Nangahar province.
"The Minister of Foreign Affairs of Afghanistan expresses its serious concern about the continuing Pakistani artillery shelling," the ministry said in a statement.
Sarkano is just across the border from the Mohmand tribal agency, where Pakistani forces launched an air and ground assault against a militant stronghold last weekend.
A Pakistan army statement on Sunday said the air and ground assault had killed 25 militants and that others had fled across the border.
The area is close to the Korengal valley, from where the United States pulled back its troops in 2010.
Pakistan complained the withdrawal opened up safe havens for militants and left it vulnerable to counterattack after it drove them out of their own tribal areas.
President Barack Obama has announced a phased withdrawl of combat troops from Afghanistan, removing 10,000 troops this year and 33,000 by the end of next summer.
(Reporting by Alistair Scrutton; Editing by Sanjeev Miglani)