MOSCOW — Russian President Vladimir Putin has said peace with Ukraine will only take place "when we achieve our objectives".

He was fielding questions from journalists and ordinary Russians in his first marathon news conference since the full-scale invasion of Ukraine began in February 2022.

Much of the largely choreographed event focused on what he calls the "special military operation in Ukraine".

He insisted the situation was improving throughout the front line.

The "direct line" program, televised for more than four hours by most major channels, began with President Putin telling Russians: "The existence of our country without sovereignty is impossible. It will simply not exist."

He added that Russia's economy was strong for a time of war and the topic of conversation quickly moved to Ukraine.

Putin said that "there will be peace [in Ukraine] when we achieve our objectives". Those "objectives do not change", he said, listing "denazification, demilitarisation and its neutral status". These are themes he has highlighted from the start of the war.

At one point he revealed that Russia currently has a total of 617,000 troops fighting in Ukraine. He also claimed that on top of 300,000 people called up for service last year, another 486,000 have signed up voluntarily as contract soldiers.

"The stream of our men who are ready to defend the interests of the homeland with weapons in their hands is not diminishing," he said. "Altogether there will be just under half a million men by the end of this year. Why do we need a mobilisation?"

He gave no number of military losses, but disclosed that children of people within his "close" circle have fought for so-called private military companies, and a number of people "close to me" have died.

A classified US intelligence report estimated this week that 315,000 Russian soldiers had been either killed or wounded since the war began -- which it said was almost 90% of Russia's military personnel at the start of the invasion.

Aside from the spontaneous questions put to Putin by Russian and international journalists, a reported two million questions were submitted for the event by ordinary Russians and carefully vetted beforehand.

A war reporter for Russian daily Izvestia based in occupied Luhansk in eastern Ukraine tasked Putin about Ukraine's recent foothold on the Russian-occupied east bank of the Dnipro river.

Describing Ukraine's military success in a "small area" as a last-ditch attempt by Ukraine to break through to Crimea, President Putin explained that Russian forces decided to withdraw several metres into wooded areas "to save our lads". He went on to suggest Kyiv's main motive is to show the West that it needs more military funding.

"I don't know why they are doing it, they are pushing their people to get killed, it's a one-way trip for Ukrainian forces. The reasons for this are political, because Ukrainian leaders are begging foreign countries for aid."

Putin said support for Ukraine from its allies was running out.

"Today Ukraine produces almost nothing," he said. "Excuse my vulgarity, but everything is being brought in as a freebie. But those freebies could run out at some point. And it seems that they are gradually running out."

While the Russian leader was speaking, Nato Secretary General Jens Stoltenberg gave a press conference at alliance headquarters in Brussels where he warned: "If Putin wins in Ukraine, there is a real risk that his aggression will not end there."

Ukraine President Volodymyr Zelensky warned the EU summit that Mr Putin would use indecision regarding the Ukraine war against them.

"People in Europe won't see any benefit if Moscow receives a pass from Brussels in the form of negativity towards Ukraine. Putin will surely use this against you personally, and against all of Europe," Mr Zelensky said via videolink.

Putin went on to claim that Russian forces had the upper hand across the front line in Ukraine.

"Practically along the entire line of contact our armed forces are improving their situation, to put it modestly," he said at his marathon news conference.

There has been very little movement on the front line in recent months, but Russia is targeting two eastern towns in the Donetsk region, Mariinka and Avdiivka.

Putin insisted that Russia could "move forward" despite Western economic sanctions and political isolation stemming from its Ukraine invasion.

He described the US as an important country but accused it of imperialism. He urged the US to "respect other people and countries" and said Russia was ready to restore relations once this happened.

New York Times correspondent Valerie Hopkins asked the Russian leader what it would take for Russia to release two American citizens held in Russian jails -- the Wall Street Journal's widely respected correspondent Evan Gershkovich and former marine Paul Whelan.

The US sees both men as wrongfully detained and Gershkovich's detention was extended on Thursday until 30 January. He was arrested while he was reporting for the newspaper in the city of Yekaterinburg and accused of espionage, which he and his colleagues firmly deny.

"As regards a possible exchange... we want to reach an agreement, and that agreement must be mutually acceptable and suit both sides," Putin responded, pointing out the men were subject to a court order.

"A dialogue on the subject is under way. It's a difficult dialogue and I won't go into the details now, but I think on the whole we're speaking in a language which we both understand. I hope we find a solution."

At one point President Putin appeared to confirm that opposition figures were being hunted in Russia.

Asked by a reporter whether the criminal code might be changed to prevent a "witch-hunt" against journalists including a pro-Kremlin colleague, Putin said: "What did she do to be hunted? What is she, some big opposition figure or something?"

Russia's biggest opposition figure, Alexei Navalny, is facing 19 years in jail and his team say they have had no access to him for more than a week. — BBC