Bulgaria has charged five people with helping one of the suspects in last weekend's bombing in central Istanbul which killed six people, prosecutors said on Saturday.
Turkey on Friday jailed 17 people over last Sunday’s blast, which Ankara has blamed on the outlawed Kurdistan Workers' Party (PKK) it designates as a “terror group.”
The victims include two girls aged nine and 15.
“Five people have been charged” over their “logistical” help to one of the suspects to flee, Siyka Mileva, a spokeswoman for the Sofia prosecutor's office told AFP.
Local television channels said three of the people charged in Bulgaria were from Moldova and a fourth was from an unspecified Arab country. There were no immediate details about the fifth person.
The PKK and its Syrian offshoot the YPG have denied involvement in the blast, which also wounded 81 people. No individual or group has claimed responsibility for the attack.
Turkish police captured the chief suspect Alham Albashir -- a Syrian woman who is said to have been working for Kurdish militants -- in an Istanbul suburb.
Albashir reportedly confessed to planting the bomb during her interrogation.
The Istanbul court remanded the 17 suspects in pre-trial detention on charges of “destroying national unity” and “deliberate killing.”
Albashir said she joined the PKK because of her boyfriend’s influence and maintained her ties to the group after she broke up with him, the Turkey’s Anodolu news agency said.
The attack was the deadliest in five years and evoked bitter memories from a wave of nationwide bombings from 2015 to 2017 that were blamed mostly on Kurdish militants and Islamic State group jihadists.