Ukraine mayor shot; hundreds attacked at rally.

Byline: Maria Danilova

KIEV, Ukraine -- The mayor of Ukraine's second-largest city was shot in the back Monday and hundreds of men attacked a peaceful pro-Ukraine rally with batons, bricks and stun grenades, wounding dozens as tensions soared in Ukraine's volatile east.

One presidential candidate said the mayor was deliberately targeted in an effort to destabilize the entire city of Kharkiv, a hub of 1.5 million people.

Russia's defense chief, meanwhile, assured U.S. Defense Secretary Chuck Hagel in a telephone call that Russia would not invade Ukraine, the Pentagon said.

Armed insurgents tacitly backed by Moscow are seeking more autonomy in eastern Ukraine -- and possibly even independence or annexation with Russia. Ukraine's acting government and the West have accused Russia of orchestrating the unrest, which they fear Moscow could use as a pretext for an invasion.

In the eastern city of Donetsk, about 1,000 demonstrators carrying Ukrainian flags marched through the streets to hold a pro-Ukrainian rally Monday night. They were attacked by several hundred armed men shouting ''Russia!''

Police attempted to hold the pro-Russia men back but then largely stood aside as dozens of protesters were battered.

Hennady Kernes, the mayor of Kharkiv, was shot in the back Monday morning while cycling on the outskirts of the city, his office said. He underwent surgery and was reported by the hospital to be in ''grave but stable'' condition.

Officials have not commented on who could be behind the attack on the mayor -- but Kernes was a man who could have angered both sides.

Kernes' friend and former Kharkiv governor, Mykhailo Dobkin, told journalists the attackers had aimed at Kernes' heart and wanted to kill him to destabilize the city

''If you want to know my opinion, they were shooting not at Kernes, but at Kharkiv,'' he said.

Dobkin is among several candidates running in Ukraine's May 25 presidential election, which the interim government says Russia is trying to derail.

Kernes was a staunch opponent of the pro-West Maidan movement that toppled President Viktor Yanukovych in February and was widely viewed as the organizer who sent activists from eastern Ukraine to harass demonstrators in Kiev.

But he has softened his stance toward the new Kiev government...