A young diplomat from Chicago has been killed in a suicide bombing along with five other Americans in the deadliest day in the war in eight months.

Anne Smedingoff, 25, is the first member of the Foreign Service killed in the 12-year-old War in Afghanistan, Daily Mail reported Sunday. She is also the first American diplomat to die overseas since the consulate attacks in Benghazi, Libya, claimed the lives of Ambassador Chris Stevens and Sean Smith.

She had been working with schools and businesses to improve the lives of girls and women in the southern province of Zabul. Smedingoff and the other Americans were on a mission to donate books to Afghan students on Saturday when their convoy was rammed by a suicide car bomber.

Smedinghoff’s father Tom told the Chicago Tribune she had met Kerry when he visited Afghanistan last month. She has helped organise the Secretary of State’s trip to the country last year, he said.

He said his daughter died doing what she loved and believed in. ‘She was living in a compound that was heavily fortified and she was always trying to get out and do things for the population,’ he said.

She joined the State Department immediately after finishing college at Johns Hopkins University in Baltimore. Her first post was in Venezuela, another nation where the US is struggling diplomatically. When her tour there ended, she volunteered to go to Afghanistan.

‘She tragically gave her young life working to give young Afghans the opportunity to have a better future,’ Kerry said in a statement. ‘We also honour the US troops and Department of Defence civilian who lost their lives, and the Afghan civilians who were killed today (Sunday) as they worked to improve the nation they love.’

Taliban spokesman Qari Yousef Ahmadi claimed responsibility for the attack in Zabul and said the bomber was seeking to target either a coalition convoy or the provincial governor .

Three Americans soldiers and a civilian Defence Department employee were killed along with Smedingoff. Four other diplomats were injured, one critically. The attack came when the Americans’ convoy intersected with a convoy carrying the provincial governor. The governor was not injured, but an Afghan doctor was killed. An American civilian adviser to the Afghan military was also killed in a separate attack in the east of the country, bringing the death toll to six. It was the deadliest day for Americans since August 16 when seven soldiers died in a pair of attacks in Kandahar.

US Secretary of State John Kerry on Sunday railed against the ‘cowardly’ terrorists responsible for the attack. At a news conference with Turkey’s foreign minister, Ahmet Davutoglu, Kerry described Smedinghoff as ‘a selfless, idealistic woman who woke up Saturday morning and set out to bring textbooks to school children, to bring them knowledge.’

‘Anne and those with her,’ Kerry said, ‘were attacked by the Taliban terrorists who woke up that day not with a mission to educate or to help, but with a mission to destroy. A brave American was determined to brighten the light of learning through books, written in the native tongue of the students she had never met, whom she felt it incumbent to help.’

Provincial Governor Mohammad Ashraf Nasery, who survived the attack in Qalat, said the explosion occurred in front of a hospital and a coalition base housing a provincial reconstruction team, or PRT. International civilian and military workers at the PRT train Afghan government officials and help with local development projects.

Nasery said the car bomb exploded as his convoy was passing the hospital. He said the doctor was killed, and two of his bodyguards and a student from the school were wounded.

‘The governor’s convoy was at the gate of the school at the same time the (coalition) convoy came out from the PRT,’ said provincial police chief General Ghulam Sakhi Rooghlawanay. ‘The suicide bomber blew himself up between the two convoys.’