KYIV -- The commander of Ukraine's armed forces has warned of possible "wide-scale aggression" by Russia against his country.

Viktor Muzhenko, the Ukrainian military's chief of staff, told RFE/RL in a February 23 interview that Kyiv's army must be prepared for any type of Russian threat amid its ongoing war against Moscow-backed separatists in the east of the country.

"We must be ready to stand against [aggression] now, tomorrow, a week after, a year after, three years after, until the moment when such a threat goes away," Muzhenko said.

The threats include a "possible wide-scale operation" and "wide-scale aggression" by Russia against Ukraine, he added.

His comments follow Ukrainian President Petro Poroshenko's signing this week of a law that supporters say will help Kyiv restore control of territory that has been held by Russia-backed separatists in Ukraine's eastern regions of Luhansk and Donetsk since April 2014.

The new law puts all military and law enforcement activities in eastern Ukraine under the control of the Ukrainian Army's top command, a move that formally ends what Kyiv has until now referred to as an "antiterrorist operation" in the area.

"The antiterrorist operation will be over and we will move further to the operations by the joint forces," Muzhenko said.

"That means a clear structure of the management system, the subordination of certain forces and resources to the military command, creation of the joint operative headquarters as the main body to manage the operation on the territories of the Donetsk and Luhansk regions," he added.

The move will help to "more effectively administer Ukraine's armed forces" in the region, Muzhenko said.

Russia has denounced the legislation, saying it threatens to escalate the violence in eastern Ukraine.

More than 10,300 people have been killed in eastern Ukraine since the fighting erupted there in April 2014 following Russia's seizure of Ukraine's Crimean Peninsula. Moscow denies backing the separatists despite substantial evidence of such support.

September 2014 and February 2015 peace deals -- known as the Minsk accords -- have failed to end the violence in eastern Ukraine. Moscow and Kyiv frequently trade accusations of undermining the peace effort.

Muzhenko told RFE/RL that Ukraine's army will be able to improve its tank defenses by the end of 2018.

He said the recent U.S. decision to supply Ukraine with more sophisticated weaponry, including Javelin antitank weapons, is important for Kyiv from a military, psychological, and political perspective.

"That is a strong political signal for other countries and also a very strong signal for Ukrainian society, saying that we are not alone, other countries are helping us, and first of all the United States is assisting us," Muzhenko said.