Turkish authorities have said it is too early to confirm whether an explosion that killed a woman at an airport in Istanbul was a bomb.
Zehra Yamac, 30, was working on her normal cleaning shift at Sabiha Gokcen airport when the blast hit in the early hours of Wednesday morning.
She was named as one of two injured staff by Pegasus Airlines, which said the incident happened on the tarmac where passengers board planes just outside the terminal building.
Ms Yamac suffered head injuries and died hours later at the Pendik Research and Training Hospital, according to Anatolia news agency.
Her colleague, Canan Celik Burgucu, 33, is being treated for hand injuries.
No one else was wounded in the blast, which was strong enough to damage several parked planes.
Sabiha Gokcen Airport, on the Asian side of Istanbul, continued operations after the explosion shortly after 2am local time (midnight GMT) as an investigation started.
“There was damage to five aeroplanes in total due to the impact of shrapnel. Weakness in the airport's security is out of the question. All international security standards are being implemented,” Binali Yildirim, the Turkish transport minister, told reporters.
“On the cause of the incident, security and intelligence teams are carrying out investigations. But it's too early to reach a verdict or comment on it yet.”
Security was increased, with armed officers setting up checkpoints at the airport’s entrances to search vehicles while a helicopter circled overhead.
Police were also seen searching the outer perimeter as part of the continuing investigation into the cause of the explosion.
Bomb attacks by Kurdish, leftist and Islamist militants are common in Turkey but there was no immediate claim of responsibility.
Isis has vowed revenge on the country for joining the US-led coalition bombing its militants in Syria, while a three-decade-old conflict between the state and the Kurdistan Workers Party (PKK) continues in south-eastern areas.
A photo on Dogan news agency's website showed a hole in one plane window. Video footage showed investigators taking photos of a terminal building wall, dozens of metres from the nearest planes.
Sabiha Gokcen is the second-largest airport in Istanbul, serving around 26 million passengers in the first 11 months of the year, less than half the number at the main Ataturk airport on the European side of the city.
Additional reporting by Reuters
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies