Pro-Russian rebels, who much of the West believe are backed by Moscow, are holding more than a dozen towns and cities in east Ukraine. The possible threat of invasion from Russia has led Ukraine to put its military on full combat alert.
The places where the insurgents are most active are:
Slavyansk – The epicentre of rebel activity and the scene of much of the reported violence and abductions. On April 12, pro-Russian gunmen seized the police building in this town of an estimated 120,000 to 140,000 people, raiding its arsenal. They then took over the town hall and the SBU security services building the same day.
Donetsk – This city of one million people is the hub of the Donetsk region, which includes Slavyansk, and is the heart of what rebels call their "Donetsk Republic". The regional administrative building was seized April 6, and the city hall on April 16.
Lugansk – This city of 465,000 inhabitants, which is also the regional heart of the Lugansk region, is proclaiming itself the core of a self-styled "Lugansk Republic". Its SBU security services building was grabbed on April 6 by some 1,000 pro-Russian protesters. On April 29, a crowd of hundreds took over the regional administrative building and later, with gunmen at their head, the regional police headquarters.
Kramatorsk – Just next to Slavyansk and 100 kilometres (60 miles) from Donetsk, this town of 160,000 inhabitants saw its town hall taken over on April 12 during a rally by more than 1,000 pro-Russian demonstrators. On April 15, a bomb alert that turned out to be false cleared the building, but militants took over the nearby SBU building. On April 21, pro-Russian militants forcibly grabbed back the town hall. A Ukraine military base lies outside the town and has fended off several attacks.
- Gorlivka (also known as Horlivka), with a population of 260,000, saw a local police building seized on April 14. On April 30, militants grabbed its regional police department and the town hall.
- Makiivka, close to Donetsk and with 360,000 inhabitants, had its town hall taken over April 13.
- Artemivsk, population 78,000, had its town hall occupied by pro-Russian activists on April 12.
- Yenakieve, population 85,000, saw the police and prosecutor's offices taken over on April 13.
- Khartsyzk, 60,000 inhabitants: Town hall seized on April 14.
- Zhdanivka, 14,000 inhabitants: Town hall seized on April 14.
- Kirovske, 28,000 inhabitants: Town hall seized on April 14.
- Torez, 80,000 inhabitants: Town hall taken on April 15.
- Kostyantynivka, 80,000 inhabitants: Town hall taken on April 28.
- Pervomaisk, 40,000 inhabitants: Town hall taken on April 29.
In a rare victory for Ukraine's security forces, the southeastern port city of Mariupol, population 480,000, was taken back from pro-Moscow rebels on April 25. But while police now control the town hall, a few pro-Russian protesters remain in the building and have not been cleared out.