On Tuesday, Vladimir Putin claimed war with Ukraine had become "inevitable"
In a rare public appearance, he said peace talks had reached a dead end and insisted the invasion - which is in its sixth week - was going as planned.
A Ukrainian official, however, told Reuters news agency that negotiations were difficult but continuing.
Mr Putin's comments were his first on the conflict in more than a week.
In contrast to the early days of the war he has more recently kept a lower profile.
He was visiting a space facility in eastern Russia with Belarusian leader Aleksandr Lukashenko, one of his closest allies, to mark the 61st anniversary of Yuri Gagarin becoming the first man in space.
The Russian leader claimed he had been left with no choice but to launch the invasion in a bid to protect Russian speakers in eastern Ukraine.
The Kremlin claims that Ukraine has committed genocide against Russian speakers in eastern Ukraine, but there is no evidence to support this,
"On the one hand, we are helping and saving people, and on the other, we are simply taking measures to ensure the security of Russia itself," the 69-year old insisted.
"It's clear that we didn't have a choice. It was the right decision," he said, adding that Russia would "rhythmically and calmly" continue the invasion.
Moscow has shifted its focus to eastern Ukraine, moving troops away from the north after encountering fierce resistance in the initial weeks of what it called its "special operation".
The UN says 10 million people have fled their homes since the invasion began.
Russian presidential spokesman Dmitry Peskov admitted last week that the country had suffered "significant losses of troops" since the conflict began.
Neither Russia nor Ukraine's estimates of Russian losses can be independently verified - and analysts have cautioned that Russia may be downplaying its casualty rate, while Ukraine could be inflating it to boost morale. Western leaders believe that between 7,000 and 15,000 Russian soldiers have been killed.
The Russian economy has also been rocked by a package of severe sanctions imposed by Western nations.
However, on Tuesday, Mr Putin said Russia did not "intend to be isolated", arguing that it was "impossible to severely isolate anyone in the modern world - especially such a vast country as Russia".
Mr Lukashenko also dismissed the impact of sanctions, asking Mr Putin: "Why on earth are we getting so worried about these sanctions?"
Last week, the UK government predicted that Russia is heading for its deepest recession since the collapse of the Soviet Union.
-- Courtesy of BBC News