Afghan security forces inspect the site of an attack in Kabul on Nov. 28, 2014. Taliban fighters staged an attack the evening before in an upscale district of the Afghan capital. (Rahmat Gul/AP)

Taliban insurgents struck targets across Afghanistan on Friday, killing at least six people and wounding scores more, extending a string of attacks in recent weeks that have put Afghans on edge, two months into the term of the new U.S.-backed government.

The most brazen assault began Thursday night, when five Taliban suicide bombers and a group of fighters tried to infiltrate Camp Bastion, an air base in the volatile southern province of Helmand, triggering an intense gun battle that lasted into Friday morning, said Omer Zowak, a spokesman for the provincial governor’s office. Afghan soldiers repelled the attack, killing at least five Taliban fighters. Two soldiers died and six were wounded in the battle.

The attack was the latest by the Islamist Taliban insurgency targeting figures and centers of authority and influence in recent weeks. British and American forces this year pulled out of Camp Bastion, a British base, and transferred it to the Afghan army. The assault exemplified how the Taliban is trying to seize advantage of a military landscape in which most American and international forces have stopped combat operations and are preparing to withdraw by the end of the year.

The attack also underscored why Afghan commanders have welcomed President Obama’s decision to expand the U.S. military role next year — from providing advice and training to allowing combat operations against the Taliban if a threat is perceived and also to provide air support to Afghan forces.

Since Afghan President Ashraf Ghani took the oath of office Sept. 29, violence by the Taliban has mounted. The growing insecurity threatens to overshadow Ghani’s trip to a donor conference in London next week, where he is to meet with U.S. Secretary of State John F. Kerry and other foreign officials to raise billions of dollars in aid to develop Afghanistan.

The assault on Camp Bastion was followed Friday by a spate of other attacks across the country, an unusually high volume for a single day, even in Afghanistan. In a separate attack in Helmand province, a suicide bomber drove a truck with explosives into a police post in Nawzad district about 8:30 a.m., killing four policemen and wounding five, Zowak said.

In Nangahar province, in the country’s east, an explosion inside a mosque during the Friday prayers, the most important of the week, wounded at least 26, including three with severe injuries, said Ahmad Zia Abdulzai, a provincial spokesman. The explosives were most likely placed in the mosque, in Khogyani district, before the prayers began, he said.

And in the northern city of Mazar-e Sharif, three fruit sellers and a passerby were wounded when a bomb exploded in a busy market, said Munir Ahmad Farhad, a spokesman for the governor of Balkh province.

The Taliban said it carried out both attacks in Helmand province but denied involvement in the mosque attack in Nangahar. No group has claimed responsibility for the attack on the market in Mazar-e Sharif.

The attacks came less than 24 hours after two suicide operations unfolded in the capital, Kabul. On Thursday, a bomber struck a British Embassy vehicle in eastern Kabul, killing six people, including a British citizen, and wounding more than 30. Hours later, three assailants targeted a guesthouse near the offices of an Arlington-based aid agency in an upscale district of the capital, triggering explosions and fierce gun battles. No civilian deaths were reported.

Mohammad Sharif contributed to this report.