US President Joe Biden resisted calls to step aside in the presidential race on Thursday during a closely-watched news conference at the end of the NATO summit in Washington.

"I'm not in this for my legacy. I'm in this to complete the job I started," Biden said. "My schedule has been full bore so if I slow down and I can't get the job done, that's a sign that I shouldn't be doing it. But there's no indication of that yet. None."

The president pushed back at every suggestion that he was slowing down or showing noticeable signs of decline at a tense news conference following a summit that was overshadowed by questions over Biden's ability to serve another four years. 

Biden says Kremlin 'lies like hell' about war in Ukraine

While showing support for Ukraine's potential NATO membership at the summit in Washington, Biden was keen to address the issue of whether he would speak to Russian President Vladimir Putin in the near future.

"I have no good reason to talk to Putin right now," he said, noting that this is because the Russian president has shown no willingness to "accommodate change in his behavior."

Biden went on to say that the Kremlin "lies like hell" about the war in Ukraine, and has already lost 350,000 troops in combat.

"I'm ready to talk to any leader that wants to talk, including Putin," he added.

Biden says war in Gaza 'should end'

Biden said his administration was making progress toward a cease-fire in Gaza, nine months into the conflict that began in the wake of Hamas's deadly attack on Israel.

"These are difficult, complex issues. There are still gaps to close. We're making progress. The trend is positive, and I'm determined to get this deal done and bring an end to this war, which should end now," Biden told reporters.

Biden mistakenly introduces Zelenskyy as Putin

Before the news conference, Biden mistakenly introduced Zelenskyy as "President Putin," raising the stakes of the event that was geared to counter fears about his fitness.

"And now I want to hand it over to the president of Ukraine, who has as much courage as he has determination. Ladies and gentlemen... President Putin," Biden said at the NATO summit, drawing gasps from those in the room.

"Going to beat President Putin, President Zelenskyy. I am so focused on beating Putin," Biden said while correcting himself.

Scholz and Macron defend Biden after gaffe

"Slips of tongue happen, and if you always monitor everyone, you will find enough of them," Scholz said when asked about the confusion between Putin and Zelenskyy.

"But this does not change a single thing of what the US president stated very clearly in his speech," Scholz said.

"We all slip up sometimes," French President Emmanuel Macron said when asked about the gaffe. "It's happened to me and it could happen again tomorrow," he said.

Macron said the US president was "in charge" and on top of matters when asked about his meeting with Biden the night before.

"I was able to talk with President Biden at length yesterday at dinner," Macron said. "I saw as always a president who is in charge, clear on the issues he knows well."

Biden mixes up Vice President Harris and Trump

Afterward, when answering the first question at Thursday night's news conference, Biden called Donald Trump his vice president, confusing him with Kamala Harris.

"I wouldn't have picked Vice President Trump to be vice president if she was not qualified to be president," Biden said.

Biden went on to say he is "the most qualified person to run for president. I beat him [Trump] once, and I will beat him again," Biden said, adding that he is "not in this for my legacy" but to "complete the job I started."

He added that he is "determined" to run in November's presidential election but it was important for him to "allay fears" among Democrats.

Biden says health in 'good shape'

Biden said his health is in good shape and that he would take a neurological exam to determine his mental acuity if his doctors recommended him to do so.

Biden said he had taken three significant and intense neurological exams, with having undergone a test most recently in February.

Doctors said he was in "good shape."

'Irreversible' path to NATO membership for Ukraine

Yesterday, NATO endorsed an "irreversible path" to membership of the military alliance for Ukraine.

Earlier on Thursday, Zelenskyy embraced the support of those countries that have provided additional military aid and a path to joining NATO, even as he emphatically pushed for the help to arrive faster.

Zelenskyy is also keen for restrictions to be lifted on the use of US weapons to attack military targets inside Russia.

"If we want to win, if we want to prevail, if we want to save our country and to defend it, we need to lift all the limitations," Zelenskyy said alongside NATO Secretary-General Jens Stoltenberg in the final hours of a meeting that saw Kyiv receive more commitments of weapons to help in its defense against Russia's invasion.

jsi/rm (AP, AFP, dpa, Reuters)