Four bombs planted in rubbish bins exploded in the Ukrainian city of Dnipropetrovsk today at short intervals, injuring 27 people, authorities said.
President Viktor Yanukovich said the bomb blasts were "a challenge ... to the whole country."
The first blast occurred at a tram stop at 11.50am. The second explosion came 30 minutes later next to a cinema, while the third blast followed shortly afterwards next to a park. The fourth explosion took place in the downtown area.
Police said the blasts had been caused by explosive devices planted in rubbish bins. Interior minister Vitaly Zakharchenko immediately left for Dnipropetrovsk to head an investigation, police said.
"No-one has been detained yet," a police spokesman said. Authorities offered no immediate explanation of any motive or say who they thought could be behind the bombs.
A man walks past damaged trams at the scene of an explosion in Dnipropetrovsk, Ukraine. Photograph: Reuters
Dnipropetrovsk, 400km southeast of the capital Kiev, is one of the former Soviet republic's biggest industrial hubs and was a key centre of the nuclear, arms and space industries in Soviet times.
The city provided a springboard for former president Leonid Kuchma, who was in office from 1994-2005, to rise to power. It is also the birthplace of jailed opposition leader Yulia Tymoshenko.
Bomb attacks have been rare in the former Soviet republic which will co-host the European football championship in June and July. But political tension is high because of the detention of Ms Tymoshenko who was jailed for seven years last October for alleged abuse-of-office which she denies.
Her imprisonment has prompted sharp criticism from Western governments which see her trial as political revenge by Mr Yanukovich, who narrowly beat her for the presidency in February 2010.
Reuters