Ukraine troops kill militants amid checkpoint clashes in Sloviansk

Russia's defense minister announced new military exercises along the Ukrainian border on Thursday just hours after Ukrainian troops killed at least two pro-Russia insurgents in eastern Ukraine.

The clashes were the first since acting President Oleksandr Turchynov ordered the resumption on Tuesday of military operations in eastern Ukraine, where pro-Russia protesters and masked gunmen have seized government buildings in at least 10 cities and set up roadblocks.

In St. Petersburg, Russian President Vladimir Putin decried what he described as Ukraine's "punitive operation" and threatened Kiev with unspecified consequences.

"If the Kiev government is using the army against its own people, this is clearly a grave crime," Putin said.

Later in the day, Russian Defense Minister Sergei Shoigu announced new military exercises in Russia's south and west in reaction to the mounting unrest in eastern Ukraine and NATO exercises in Poland.

"We have to react to these developments somehow," he said in televised comments.

Russia already has tens of thousands of troops stationed in regions along its border with Ukraine. The latest Russian military exercises will involve ground troops in the south and the west and air forces patrolling the border, Shoigu said.

He also quoted unspecified sources as saying that Kiev has deployed more than 11,000 troops and 160 tanks against the pro-Russia insurgents, whose numbers he put at less than 2,000. There was no way to immediately verify those figures.

The Ukrainian government and the West have accused Russia of directing and supporting the insurgents, and they worry that Putin would welcome a pretext for a military intervention in eastern Ukraine. Putin denies that any Russian agents are operating in Ukraine, but he insists he has the right to intervene to protect the ethnic Russians who make up a sizeable minority in eastern Ukraine.

Earlier in Tokyo, US President Barack Obama accused Moscow of failing to live up to "the spirit or the letter" of a deal last week to ease tensions in eastern Ukraine. If that continues, Obama said, "there will be further consequences and we will ramp up further sanctions."

"I understand that additional sanctions may not change Mr. Putin's calculus," Obama said during his Tokyo visit. "How well they change his calculus in part depends on not only us applying sanctions but also the cooperation of other countries."

The Ukrainian Interior Ministry said military and special police forces killed "up to five terrorists" while destroying three checkpoints north of Sloviansk, a city 160 kilometers west of the Russian border that has emerged as the focus of the armed insurgency. One government member was injured, the statement said.

Stella Khorosheva, a spokeswoman for the Sloviansk insurgents, said two pro-Russia fighters were killed at a checkpoint in the village of Khrestyshche, 10 kilometers north of the city. She said checks were being made at hospitals to see if there were other casualties.

Khorosheva later said the pro-Russia militia had regained control over the disputed checkpoints and the fighters were ready to repel any attack by government troops.