Russian President Vladimir Putin said Moscow sent the first batch of nuclear arms to its neighbor Belarus following an agreement signed last month.
"The first nuclear charges were delivered to the territory of Belarus," Putin said at a plenary session of the St. Petersburg International Economic Forum, underlining that more deployments would be made in the coming months.
"This is the first part. But by the end of the summer, by the end of the year, we will complete this work entirely," he said, calling the move an "element of deterrence."
In late May, Russian and Belarusian defense ministers signed an agreement on the deployment of Russian nuclear weapons in Belarus, which stipulates terms for keeping them in a special storage facility.
Earlier this year, Putin announced that Russia will deploy tactical nuclear weapons and complete the construction of a special storage facility for them in neighboring Belarus.
During his speech, Putin also referred to Ukraine's ongoing efforts to recapture parts of the country controlled by Russian forces, saying Kyiv's push had only reached Russia's "first line" in some areas and failed to achieve its goals.
He claimed that the cost of Ukraine's long-awaited counteroffensive has been high and that Kyiv has suffered severe human losses.
"In some places, Ukrainian units manage to reach the first line. In some places, they fail ... The important thing is that they are using strategic reserves ... and that they have not achieved their goals at any of the sites," he said.
This came after Ukrainian claims that Kyiv had made progress against Russian troops in multiple directions, including toward Bakhmut, a major hot spot in the Russia-Ukraine war.
Putin pointed out that Moscow had made progress toward its goal of "demilitarizing" Ukraine, with arms production in the country having come to a near standstill as most weapons are imported from abroad.
Russia, meanwhile, has stepped up military production 2.7 times and continues to develop its capacities, he added.
"As we speak, another attempt is being made. The opponent is trying to attack in several areas. They've come to the first edge, the battle is going on right at this moment," he said.
Putin ruled out the prospect of a Ukrainian victory in the fresh assault and the war overall.
He said German Leopard tanks, delivered to Ukraine earlier this year, "are burning" on the battlefield, adding that if U.S.-made F-16 fighter jets are also given to Kyiv, they would be shot down.
"NATO is getting involved in the war in Ukraine ... The F-16s will also burn, there is no doubt about it. But if they are located at air bases outside Ukraine, we will have to look at how and where to hit those arms that are used against us. This is a serious danger," said Putin.
Putin said Russia was capable of launching strikes at government buildings in Kyiv but did not for reasons he would not voice publicly.
Asked about the possibility of a Russian tactical nuclear strike in the ongoing conflict, Putin said Russia was not inclined to carry out such an attack, adding that nuclear arms should only serve as a deterrent.
He also criticized assertions that recent agreements with China were making Moscow beholden to Beijing.
Putin said other countries, including those making such claims, had already become dependent on China "a long time ago."
"When I hear, 'you will become dependent on China,' I ask, 'and you? ... You've already become so a long time ago," he said, adding that "nothing" negative had come of such relations with Beijing.
Amid rising efforts to ditch trade in U.S. dollars in favor of national currencies, Putin said Moscow did not want to refuse payments in the American currency but that this was a likely outcome.
"If this trend gains momentum in stock exchanges, if other oil and gas exchanges appear where payments are not carried out in dollars, this will be the beginning of the end for the dollar," he said.