Heraldo de Madrid - Thousands of Afghans displaced by Pakistan conflict

The neighbours have clashed along the frontier since Thursday, when Afghanistan launched a border offensive in retaliation for Pakistani air strikes.

Islamabad has hit back along the border and with fresh air strikes, bombing multiple sites including the former US air base at Bagram, the capital Kabul and the southern city of Kandahar.

"Due to these brutal bombings and attacks, 8,400 of our families have been displaced, forced to leave their villages and homes," Afghan deputy government spokesman Hamdullah Fitrat said at a news conference.

An AFP journalist near the frontier has spoken to residents who have fled the clashes.

Afghanistan's defence ministry reported "extensive and heavy offensive and revenge attacks" across seven provinces over the past day.

The government acknowledged earlier air strikes on Bagram for the first time.

"Yes, the enemy targeted Bagram as well, but there were no casualties or damage," defence ministry spokesman Enayatullah Khowarazmi said.

Two residents told AFP on Sunday that they heard air strikes in Bagram, north of the capital.

Pakistani security sources said strikes at Bagram were based on "credible intelligence" to disrupt the "supply of critical equipment and stores" for Afghan soldiers and militants fighting Pakistan forces along the frontier.

They said Pakistan reserves the right to respond to the Taliban government's "aggression along its border by striking legitimate targets at the time and place of its own choice".

Pakistani figther jets also flew nighttime sorties over Kabul, another security source told AFP.

- UN 'alarmed' -

Islamabad's confirmation that its aircraft flew over the Afghan capital came hours after AFP journalists in the city heard multiple explosions.

The blasts were heard alongside anti-aircraft weapons and gunfire from across the city.

An AFP journalist in Jalalabad city, between Kabul and the frontier, reported hearing explosions and various weapons being fired.

At the nearest border crossing, around 50 kilometres (30 miles) from Jalalabad, residents in Torkham told AFP the days-long fighting was ongoing.

The latest casualties include three children killed in a "crime committed by the Pakistani military regime" in Kunar province, Fitrat said Monday.

At least 39 civilians have been killed since Thursday, the Afghan government said, a toll which Pakistan has not commented on.

The UN children's charity said it was "alarmed" by reports of child casualties in the conflict, and called on all sides to "exercise maximum restraint, protect civilian lives".

Pakistan said its February air strikes that sparked the escalation were targeting militants.

Islamabad accuses Afghanistan of failing to act against militant groups that carry out attacks in Pakistan, which the Taliban government rejects.

The Afghan defence ministry spokesman said more than 25 soldiers have been killed, while estimating Pakistani fatalities among troops at around 150.

Pakistan says more than 430 Afghan soldiers have been killed, with more than 630 wounded.

Casualty claims from both sides are difficult to verify independently.

The violence of recent days is the worst since October fighting killed more than 70 people on both sides, with land borders between the neighbours largely shut since.

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N.Carrasco--HdM