Live Blog: Crisis In Ukraine (Archive)

This snippet from Rossiya-24 television purports to show a Ukrainian helicopter being shot down by pro-Russian militants in Slovyansk:

Russian news agency Interfax is quoting pro-Russian militant spokeswoman Stella Khorosheva in Slovyansk as saying "one was killed and another one was injured on the militia's side" during fighting there on May 2. The pro-militant website Slavgorod.ua is reporting that Sloyansk residents are forming a "human shield" at a roadblock in Cherevkovka.

In an interview with the "Financial Times," acting Ukrainian Prime Minister Arseniy Yatsenyuk described the period between May Day and Victory Day (May 9) at "the most dangerous 10 days" for Ukraine since 1991. He said Moscow is planning clashes during events that evoke nostalgia for the Soviet Union and said there are "10-20 well-trained Russian agents" working in eastern Ukraine, moving from one town to another.

RFE/RL on April 30 published a "reporter's notebook" from Donetsk about the failure of the Geneva agreement to have any impact there and about the mounting anxiety about what may happen in the next week.

Here is the latest from RFE/RL's news desk on the situation in eastern Ukraine:

Ukraine's Defense Ministry has confirmed that two of its helicopters were shot down and the pilots killed in a major offensive to retake the eastern city of Slovyansk.

Interior Minister Arsen Avakov said on Facebook the goals of the offensive are to "free the hostages, lay down their arms, and free administrative buildings, and restore the normal functioning of the town's administration."

Slovyansk, which has a population of some 140,000 people, has been under the control of the pro-Russian separatist forces since last month.

Avakov said separatists had fired antiaircraft missiles and used heavy artillery and grenades.

He said Ukrainian troops had taken control of nine checkpoints on roads around the city.

Avakov said, "It's a real battle we are waging against professional mercenaries."

Separatists described the Ukrainian offensive as "large-scale."

A plume of black smoke was seen rising on the outskirts of the city. Correspondents report gunfire and explosions. An AFP reporter saw a column of eight Ukrainian armored vehicles breaching a rebel-held checkpoint just south of Slovyansk.

The rebels have detained Slovyansk's mayor, several journalists, three Ukrainian Security Service members, and are also holding a team of OSCE military observers.

Meanwhile, in Donetsk,the provincial capital about 100 kilometers south of Slovyansk, hundreds of pro-Russian separatists stormed the local prosecutor's office on May 1.

They pelted police with stones and beat them before stripping them of their riot gear and running them away from the building.

In Kyiv, acting Ukrainian President Oleksandr Turchynov has signed an order reinstating military conscription. The order comes into effect immediately.

Turchynov said in a statement the move was necessary "given the deteriorating situation in the east and the south...the rising force of armed pro-Russian units, and the taking of public administration buildings...which threaten territorial integrity."

In Israel, the mayor of the eastern Ukrainian city of Kharkiv, Hennadiy Kernes, has regained consciousness.

Kernes was flown to Israel after being shot by unknown assailants on April 28.

Kernes first held a pro-Russian stance, but later positioned himself as loyal to the pro-Western government in Kyiv.

In Washington, NATO Deputy Secretary-General Alexander Vershbow says the alliance must reconsider its position toward Russia.

Vershbow said on May 1 in Washington that despite trying for some 20 years to build a partnership with Russia, Moscow has "declared NATO as an adversary."

Because of that, he says NATO must now also "begin to view Russia no longer as a partner but as more of an adversary."

Unconfirmed report:

For background, Reuters has this piece on how Russia has reformed its military since the 2008 war with Georgia. "The result...is a more streamlined force that can mobilize key units in a matter of days and support President Vladimir Putin's goal to reassert Russian influence over countries it once controlled within the former Soviet Union."

Purported photograph of locals blocking a road near Andreyevka after Ukrainian forces dismantled a roadblock:

If you read Russian, RIA-Novosti has a Ukraine liveblog running now here. RFE/RL's is better, but in the interests of complete information....

Writing in "The Guardian," columnist Seumas Milne explains the Ukraine crisis from the Kremlin's point of view.

"The reality is that, after two decades of eastward Nato expansion, this crisis was triggered by the west's attempt to pull Ukraine decisively into its orbit and defence structure, via an explicitly anti-Moscow EU association agreement. Its rejection led to the Maidan protests and the installation of an anti-Russian administration – rejected by half the country – that went on to sign the EU and International Monetary Fund agreements regardless.

No Russian government could have acquiesced in such a threat from territory that was at the heart of both Russia and the Soviet Union. Putin's absorption of Crimea and support for the rebellion in eastern Ukraine is clearly defensive, and the red line now drawn: the east of Ukraine, at least, is not going to be swallowed up by Nato or the EU."

There have been several alarming, but unconfirmed reports that BuzzFeed journalist Mike Giglio and his local fixer have gone missing near Slovyansk: