Peskov said that people in the Ukrainian regions of Kherson, Zaporizhzhia and Donbas must decide their own futures and the Kremlin did not doubt they would make the "best decision". Ukraine has previously said that annexation of the regions by Russia would end peace talks between the two sides.
Meanwhile, Russia has sharply criticised a US decision to supply advanced rocket systems and munitions to Ukraine, warning of an increased risk of a direct confrontation between the two superpowers.
Russian Deputy Foreign Minister Sergei Ryabkov told state news agency RIA Novosti that Moscow viewed US military aid to Ukraine "extremely negatively".
He blamed Washington for escalating hostilities in Ukraine, saying: "The U.S. does nothing in the interests of finding some kind of solution. It was precisely the same for many years before the beginning of the special military operation."
President Vladimir Putin launched what Russia calls a "special operation" on Feb. 24 to disarm and "denazify" Ukraine. Ukraine and its Western allies call this a baseless pretext for an unprovoked war of aggression.
A US official told reporters the weapons being sent are Himars, or the High Mobility Artillery Rocket System, which have precision-guided munitions and a longer range than those currently deployed by Ukraine.
The Himars are the centrepiece of a $700 million package being unveiled Wednesday that includes air surveillance radar, more Javelin short-range anti-tank rockets, artillery ammunition, helicopters, vehicles and spare parts, the official said.
Meanwhile, in Brussels, European Union leaders were split over banning natural gas from Moscow after agreeing to embargo two-thirds of its oil to tighten the economic screws.
Russia's invasion of Ukraine is threatening a global food crisis, with Ukraine's huge grain harvest effectively taken off the world market. French President Emmanuel Macron said Tuesday that he and German Chancellor Olaf Scholz had urged Russian leader Vladimir Putin to end Russia's blockade of the Ukrainian port of Odessa.
But Russian Foreign Minister Sergei Lavrov said it was up to the West and Kyiv to resolve the crisis, starting with the lifting of sanctions.
