Zenit's St.Petersburg soccer club players pay respect at a symbolic memorial at Technologicheskiy Institute subway station in St. Petersburg, Russia, April 5, 2017. A bomb blast tore through a subway train deep under Russia's second-largest city St. Petersburg Monday, killing several people and wounding many more in a chaotic scene that left victims sprawled on a smoky platform. Cyrillic letters on white shirts read: We Are Unbreakable.(AP Photo/Dmitri Lovetsky)
Russian police arrested three people suspected of ties to
Akbarjon Djalilov, the man accused of a suicide bombing in a St. Petersburg subway station that killed 13 people and himself earlier this week.
Investigators found parts of a bomb in the people's apartment. They are all residents of Central Asia, as was Kyrgyzstan native Djalilov. Thousands of people from that region are believed to have joined ISIS.
The square outside the Sennaya metro station has become a makeshift memorial.
On Wednesday, eight other people suspected of being ISIS and Al-Qaida recruiters were arrested in Russia. They were not suspected of being tied to the subway attack.
No terrorist group has yet claimed responsibility for the deadly attack.
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People react at a symbolic memorial at Technologicheskiy Institute subway station in St. Petersburg, Russia, Wednesday, April 5, 2017. Investigators searched for possible accomplices of a 22-year-old native of the Central Asian country of Kyrgyzstan identified as the suicide bomber in the St. Petersburg subway, as residents came to grips with the first major terrorist attack in Russia's second-largest city since the Soviet collapse. (AP Photo/Dmitri Lovetsky)
Yevgeny Kurskov/AP
Young people hold candles as they gather to honor the memory of the victims of subway bombing on Marsovo Polye in St. Petersburg, Russia, Wednesday, April 5, 2017. A bomb blast tore through a subway train under Russia's second-largest city on Monday, killing several people and wounding more. (AP Photo/Yevgeny Kurskov)
Yevgeny Kurskov/AP
People cry at a symbolic memorial at Technologicheskiy Institute subway station in St. Petersburg, Russia, Wednesday, April 5, 2017. A bomb blast tore through a subway train deep under Russia's second-largest city St. Petersburg Monday, killing several people and wounding many more in a chaotic scene that left victims sprawled on a smoky platform.(AP Photo/Dmitri Lovetsky)
Dmitri Lovetsky/AP
People form digits of the time of the subway bombing in memory of victims of the tragic event, on Marsovo Polye in St.Petersburg, Russia, Wednesday, April 5, 2017. A bomb blast tore through a subway train under Russia's second-largest city on Monday, killing several people and wounding more. (AP Photo/Dmitri Lovetsky)
Dmitri Lovetsky/AP
Dmitri Lovetsky/AP
People stand around candles showing the time of the subway bombing as they gather in memory of victims of the tragic event, on Marsovo Polye in St. Petersburg, Russia, Wednesday, April 5, 2017. A bomb blast tore through a subway train under Russia's second-largest city on Monday, killing several people and wounding more. (AP Photo/Dmitri Lovetsky)
Dmitri Lovetsky/AP
Dmitri Lovetsky/AP
A man fixes Russian flag at a symbolic memorial at Technologicheskiy Institute subway station in St. Petersburg, Russia, Wednesday, April 5, 2017. A bomb blast tore through a subway train deep under Russia's second-largest city St. Petersburg Monday, killing several people and wounding many more in a chaotic scene that left victims sprawled on a smoky platform.(AP Photo/Dmitri Lovetsky)
Dmitri Lovetsky/AP
Dmitri Lovetsky/AP
Zenit's St.Petersburg soccer club players pay respect at a symbolic memorial at Technologicheskiy Institute subway station in St. Petersburg, Russia, April 5, 2017. A bomb blast tore through a subway train deep under Russia's second-largest city St. Petersburg Monday, killing several people and wounding many more in a chaotic scene that left victims sprawled on a smoky platform. Cyrillic letters on white shirts read: We Are Unbreakable.(AP Photo/Dmitri Lovetsky)
Dmitri Lovetsky/AP
A woman prays during a religious service for victims of a subway explosion, in a cathedral in St.Petersburg, Russia, Wednesday, April 5, 2017. Investigators searched for possible accomplices of a 22-year-old native of the Central Asian country of Kyrgyzstan identified as the suicide bomber in the St. Petersburg subway, as residents came to grips with the first major terrorist attack in Russia's second-largest city since the Soviet collapse. (AP Photo/Dmitri Lovetsky)
People light candles during a religious service for victims of a subway explosion, in a cathedral in St.Petersburg, Russia, Wednesday, April 5, 2017. Investigators searched for possible accomplices of a 22-year-old native of the Central Asian country of Kyrgyzstan identified as the suicide bomber in the St. Petersburg subway, as residents came to grips with the first major terrorist attack in Russia's second-largest city since the Soviet collapse. (AP Photo/Dmitri Lovetsky)
Here's another look at the memorials near the station.
