Afghan police on Sunday sought to free five local Red Cross employees kidnapped by gunmen in the western province of Herat, in the latest case of aid workers being targeted.
The International Committee of the Red Cross (ICRC) team were taken hostage as they travelled by road to deliver aid in Herat, which has seen worsening violence in recent months.
"The five Red Cross staff were kidnapped on Thursday," Najib Danish, deputy spokesman at the interior ministry, told AFP.
"The police have launched a search and rescue operation to find them. Elders in the area are also helping to track them down."
Marek Resich, the ICRC spokesman in Kabul, said that the five staff had been taken by a local armed group.
"The ICRC is currently in contact at various levels to secure the safe release of its team," he said. There was no claim of responsibility from the Taliban or other insurgent groups.
The kidnapping comes after other targeting of aid workers, notably when two Finnish humanitarian workers travelling in a taxi in Herat city were shot dead by armed men at the end of July.
Violence against Westerners has been growing in Afghanistan as foreign troops wind down combat operations after a 13-year war against the Taliban, with the majority of NATO's 44,000 troops due to leave by the end of the year.
Afghanistan is one of the most dangerous countries in the world for aid workers, along with South Sudan, Syria and Somalia.
Of the 248 attacks against humanitarian workers worldwide in 2013, 81 were in Afghanistan, according to specialist website Aid Worker Security.
More than 30 aid workers were killed in Afghanistan last year, including six Afghan employees of the Agency for Technical Cooperation and Development (Acted), who were shot while working on a rural development project in the northern province of Faryab.
Five Afghans working for the International Rescue Committee were also killed by armed gunmen in Herat one year ago.
In 2010 the Taliban claimed responsibility for killing 10 employees of the International Assistance Mission group -- six Americans, a German, a Briton and two Afghans -- in the east of the country, claiming they were "Christian missionaries".