The first meeting between Biden, Putin, U.S. Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov has concluded after about an hour and a half, according to a White House and Russian officials.

"They are moving into the expanded bilateral meeting," a White House official said, with five aides present on each side, including the U.S. and Russian ambassadors.

On the U.S. side, Blinken, national security adviser Jake Sullivan, Undersecretary of State for Political Affairs Victoria Nuland, U.S. Ambassador to Russia John Sullivan and National Security Council Russia experts Eric Green and Stergos Kaloudis, are accompanying Biden.

The Russian delegation is expected to include Lavrov, Putin’s foreign affairs adviser Yuri Ushakov, Lavrov’s deputy Sergei Ryabkov, the chief of the General Staff of the Russian military Gen. Valery Gerasimov, Russian ambassador to Washington Anatoly Antonov. Kremlin envoys on Ukraine and Syria, as well as Putin’s spokesman, Dmitry Peskov, are also expected to attend.

-ABC News' Ben Gittleson

In a photo-op surrounded by chaos, some reporters were let inside a small door leading to the room where Biden and Putin were already sitting down for the first meeting of their summit.

"I would like to thank you for your initiative in today's meeting," Putin said, according to a transcript from the Kremlin. "I know you've had a long trip, a lot of work. Nevertheless, there are many issues in Russian-American relations that need to be discussed at the highest level, and I hope that our meeting will be productive."

Biden replied, "Thank you, as I said outside, I think it's always better to meet face-to-face. I’m trying to determine where we have mutual interests and we can cooperate. And where we don't, establish a predictable and rational way in which we disagree. Two great powers."

The summit is expected to go as long as five hours, and while the two leaders are expected to take breaks and expand their meeting to a larger group, no updates are expected until their dueling solo press conferences later.

At least two American reporters who made it inside the meeting said afterward that Russian security pulled on their clothes as they tried to push the journalists out.

When Russian security yelled and shoved at journalists to get out, both press and White House officials "screamed back that the Russian security should stop touching us," according to a pool reporter.

"Both presidents watched and listened to the media scuffle in front of them. They appeared amused by the scene," the reporter said.

The media scrum also appeared to momentarily delay the Swiss president’s departure from the villa. His motorcade pulled up for him to leave, and officials or security tried to move the reporters out of the way. The Swiss president came out and was able to pull away.

One critical message the president will carry, according to U.S. Secretary of State Antony Blinken, is demanding that Russia stop "harboring in any way criminal organizations engaged in cyberattacks, including ransomware" and urging "Russian cooperation in dealing with these criminal organizations to the extent they're operating from Russian territory."

But tough talk and mounting U.S. sanctions have not deterred Russian behavior, from crackdowns against domestic political opposition and pro-democracy movements to aggression overseas against neighbors Ukraine and Georgia or western democracies and their elections.

Pressed on that Sunday by ABC "This Week" co-anchor Martha Raddatz, Blinken said U.S. sanctions "can be" effective, "especially when they're done in coordination with other countries."

To that end, he emphasized what the administration had said was the importance of Biden meeting American allies in the Group of Seven, NATO and the European Union before sitting down with Putin.

But some of those alliances are bruised after four years of former President Donald Trump's badgering and questioning -- with many Europeans in particular unsure whether "Trumpism" is here to stay or whether "America is back," as Biden has made his tagline for this trip.

Blinken didn't take that political question head on, but he said the U.S. and its allied democracies have "to actually demonstrate in concrete ways that democracies working together are making a difference for their people and for people around the world" -- especially in contrast to Russia and China.

-ABC News' Conor Finnegan

When Putin meets Biden on Wednesday in Switzerland, experts in Moscow say for all their differences, the two leaders want something similar from their first summit: to cool things down.

The U.S. and Russia's relations are the worst they have been since the Cold War and since 2016 in particular seem locked in almost permanent crises.

Biden has said he wants a more stable and predictable relationship with Russia, one that would allow it to focus on other foreign policy priorities that are more important to it, like taking a harder line with China. The Kremlin for its part has faced a continuous and intensifying barrage of sanctions-- the latest in April-- and with its crackdown on opposition at home and aggressive actions abroad is increasingly becoming a pariah with western countries.

Since coming to office, Russia has appeared to want to get Biden's attention. The president offered Putin the summit after Russia massed thousands of troops on Ukraine's border in April.

But now, having got Biden to the table, analysts said Putin has a clear proposal to deliver in Geneva: stay out of Russian domestic politics and Russia might act less troublesome abroad.

"The Kremlin wants to transition to a respectful adversarial relationship from a disrespectful one we have today," said Vladimir Frolov, a former diplomat at Russia's embassy in Washington and now a commentator on foreign affairs.

"That is, it wants to be treated the same way the Soviet Politburo was treated by the US in 1970-80s," Frolov told ABC News. "Meaning no name-calling" — such as Biden calling Putin a "killer" — "no personal sanctions on the leadership, no democracy lectures, regular personal summit meetings; respectful tone of discussions, no tangible support for Russian opposition."

It will not be an invitation for détente but instead to return to the later years of the Cold War when Putin was a KGB agent and the Soviet Union and the U.S. saw each other as enemies but tried to maintain a predictable relationship. And, crucially, where Russia was treated as an equal.

"For this, the Kremlin is prepared to promise to behave more responsibly," Frolov said.

"This seems to be in line with what the White House sees as a desirable deliverable," he continued. "So unless one of the leaders stormed out of the meeting shouting expletives, the summit would be a major success."

-ABC News' Patrick Reevell