Gunmen abducted six Red Cross aid workers and a local volunteer of the Syrian Arab Red Crescent in northwest Syria on Sunday, the International Committee of the Red Cross (ICRC) said.
The humanitarian agency had no contact with the unidentified gunmen, ICRC spokesman Ewan Watson said, declining to reveal the identity, nationalities or gender of the six ICRC staff for now.
"We call for the immediate and unconditional release of the seven colleagues abducted this morning," Magne Barth, head of the ICRC's delegation in Syria, said in a statement.
The team had gone to Idlib on Thursday to assess the medical situation in the province and to deliver medical supplies to Sarmin and Idlib city, it said. The convoy was clearly marked with the ICRC emblem when stopped near Sareqeb on the way back to Damascus, it added.
"Both the ICRC and the Syrian Arab Red Crescent work tirelessly to provide impartial humanitarian assistance for those most in need across Syria on both sides of the front lines, and incidents such as these potentially undermine our capacity to assist those who need us most," Barth said.
Syrian state media reported the incident earlier in the day, saying the gunmen had kidnapped the Red Cross workers after opening fire on their vehicles on Sunday.
Quoting an unnamed official, state news agency SANA said the workers were travelling in the Idlib area when gunmen blocked their path, shot at their convoy, seized them and took them to an unknown location.
"An armed terrorist group today kidnapped a number of workers in the mission of the International Committee of the Red Cross in Syria," the report said, using a term the government frequently uses for rebels trying to topple President Bashar al-Assad.
Watson was not able to confirm that shots had been fired, but said the team's vehicles were also missing.
Kidnappings have become increasingly common in northern Syria, where rebels have captured swathes of territory but government forces have clung on to many urban centers and fighting continues daily.
The ICRC and Syrian Arab Red Crescent are the main aid groups deployed in Syria's civil war, distributing their own supplies and most of those sent by United Nations agencies.
They have to negotiate the passage of aid convoys with a growing number of groups within the fractured opposition, ICRC officials say.
"Whether in the north or other regions of the country where the opposition groups are strongly present, it is the multiplicity of groups that makes the dialogue challenging," Pierre Kraehenbuehl, the ICRC's operations director, told reporters at its Geneva headquarters last month.
"Criminal actors" were also part of the challenging scenario in Syria, he said.
The 2-1/2-year conflict has claimed more than 100,000 lives and driven more than 2.1 million refugees out of their homeland.
"The ICRC is committed to assisting the Syrian people and will continue conducting its humanitarian activities both in the country and in neighboring countries for refugees there," Barth said in the statement.
Syrian authorities on Sunday allowed 3,500 people to leave Moaddamiyah, a besieged town in the Damascus region, Watson said.
"We and the Syrian Arab Red Crescent are assisting those people with emergency relief items including food and water," he said.