"We have always tried to be predictable partners, handle business on an equal basis, but in return our legal interests were partially ignored and are still ignored. Russian and U.S. contacts have a great meaning for the entire world.

"We are ready for constructive dialogue, but again I emphasize only on equal terms."

Russia's ambassador to the European Union, Vladimir Chizhov, said Tuesday that the refusal to extend the cease-fire is a "negative sign," the Russian Foreign Ministry said on Twitter.

"This makes it even harder to understand the logic of how the confirmation of the so-called 15-point peace plan correlates with the refusal to prolong truce," Chizhov was quoted as saying by state news agency ITAR-Tass.

'Enemies and invaders'

Poroshenko declared in a late-night televised address that the cease-fire was over.

In Kiev's Independence Square, known as Maidan, activists outside the presidential administration building applauded Poroshenko's stance.

"We need only military actions," a priest named Valentyn said in a Reuters interview. "We were forced by those who entered our country as enemies and invaders."

The crisis has its roots in former President Viktor Yanukovych's decision last year to shun a European Union Association Agreement and turn toward Russia instead. The move unleashed deadly strife that led to Yanukovych's ouster, Ukraine's loss of Crimea, and a pro-Russia separatist rebellion. Russia also massed troops along its western border with Ukraine.

The Association Agreement, which will bring closer trade and political ties between Ukraine and Europe, was finally signed by Poroshenko and European leaders last week.

After Monday's phone call, Poroshenko said his goal was peace but insisted it takes the participation of all parties to maintain stability, noting violations of the cease-fire by pro-Russia separatists.

The Ukrainian government "has been completely fulfilling its commitments and unilaterally complying with the ceasefire regime for 10 days and paid dozens of lives for that," he said.

Peace talks were held last week among Ukrainian government officials, pro-Russia separatists from the restive eastern Luhansk and Donetsk regions, Russian officials, and members of the Organization for Security and Cooperation in Europe.

'Bloody truce'

Activist Vadym told Reuters there was no point in continuing the cease-fire.

"There is definitely no need for an extension of the truce," he said. "Because a lot of our boys died during this truce."

Fellow activist Yulia agreed.

"Bloody military actions are better than such bloody truce," she said. "We must put an end to it once and that's all."

A statement from Putin's press office about the call said the Russian President "stressed the need to extend the cease-fire and also establish a reliable mechanism for monitoring" it.