KABUL, Afghanistan (AP) — A roadside bomb killed a district police chief and his two bodyguards in a restive southern province in the second attack in as many days targeting local authorities in Afghanistan, police officials said Monday.

The roadside bomb in Helmand exploded as Mohammad Saifullah, the police chief in the province’s Garm Ser district, was driving by Sunday night, said Helmand provincial police chief Mohammad Hakim Angar. All three men were killed by the blast.

The province is one of Afghanistan’s most violent, and sits in the heart of the Taliban’s traditional stronghold in the south.

Security responsibilities in Helmand’s capital have already been handed over to Afghan forces by NATO, as part of the U.S.-led coalition’s plan to withdraw its combat troops from the country by the end of 2014. Two other districts in the province are being recommended for an upcoming second phase of handovers, but Garm Ser is not among them.

The police official’s death comes a day after a suicide bomber blew himself up among worshippers concluding prayers on the first day of a main Islamic holiday, killing seven people including two local police officials, in the northern province of Baghlan. A second would-be suicide bomber was captured before detonating his explosives.

The attacks are part of the insurgency’s strategy of targeting Afghan government and security officials, and raise questions about Afghan security forces’ ability to take on the Taliban by themselves after NATO withdraws its combat forces.

The U.S.-led coalition has said it has made significant gains in curtailing the Taliban’s strength.

The coalition’s push in the south of the country, the Taliban’s traditional stronghold, has to a degree lessened the violence. But it has also pushed them to other parts of the country where attacks had been less common.

In the eastern province of Nangarhar’s Behsud district, a combined Afghan and NATO force killed one Afghan and wounded another during an operation targeting a Taliban facilitator who provided logistical support and weapons to insurgents in the area, NATO said in a statement Monday. Two suspected insurgents were detained. The statement did not make clear whether the man killed was a suspected insurgent.

Afghanistan’s eastern border with Pakistan is a particular source of concern for NATO. The area is rife with militant activity, including the al-Qaida and Taliban-linked Haqqani network that operates from what Afghan and coalition officials say are safe havens in Pakistan.

Also in the east, NATO said an Afghan male was shot dead by a joint coalition-Afghan force after he failed to comply with orders and "displayed hostile intent toward the security force." The incident occurred as the troops were searching for a Haqqani facilitator in Badakshan province’s Argo district, NATO said.