KABUL, Afghanistan (AP) — At least four civilians were killed in their homes by militant rocket fire in northern Afghanistan on Thursday, the country's Ministry of Defense said.

The ministry statement blamed the Taliban for the firing, which it said wounded another 14 civilians and destroyed several houses in the Sharin Tagab district of Faryab province.

No one immediately claimed responsibility for the attack.

A recent increase in violence nationwide comes as Afghan government representatives and the Taliban are holding peace talks in Qatar, where the Taliban have for years maintained a political office. The negotiations, envisaged under a U.S. deal signed with the insurgents in February, are meant to end Afghanistan’s grueling 19-year war and are seen as the country’s best chance at peace.

The Trump administration has pledged to pull out American forces from Afghanistan, but U.S. officials have stressed that the Taliban have still not met requirements to reduce violence against Afghans, a key element of the U.S. withdrawal plan.

The U.S. special envoy to Afghanistan, Zalmay Khalilzad, warned earlier this week that the “distressingly high” levels of violence threaten to derail the peace talks.

His comments came as days of renewed fighting have plagued the southern Helmand province, a longtime Taliban stronghold. The Taliban last Friday agreed to halt their attacks on condition that the U.S. stop its airstrikes in the area.

In Helmand, two civilians and three police officers were killed late Wednesday when their vehicle hit a roadside bomb in the provincial capital of Lashkar Gah, said the governor’s spokesman Omer Zwak. No one claimed responsibility for the bombing.

Elsewhere, in the northern Takhar province, the Ministry of Defense claimed at least 12 Taliban insurgents were killed in a strike conducted by Afghan warplanes on Wednesday afternoon.

However, local officials said all 12 of those killed were civilians, and that the airstrike targeted a mosque. The officials, who spoke on condition of anonymity because they were not authorized to speak to reporters, said 16 others were wounded.

The Ministry of Defense said it was investigating the allegations of civilian casualties in the airstrike.

On Tuesday, at least 36 Afghan police were killed in an ambush claimed by the Taliban in northern Afghanistan — the deadliest attack since the long-delayed peace talks began last month.

On Sunday, a suicide car bombing killed at least 13 people and wounded around 120 others in the western Ghor province. Although no one claimed responsibility for the bombing, suspicion immediately fell on the Taliban.