US President Joe Biden said Wednesday that the world was "turning the tide" toward freedoms.
Biden, speaking at the White House to the mostly virtual gathering of 121 leaders, formally announced $690 million in new funding to support democracy around the world.
"I believe this is the defining challenge of our age, Biden said.
Biden, who invited eight more leaders than at his inaugural 2021 democracy summit, cited efforts by Angola to build an independent judiciary and anti-corruption plans by the Dominican Republic and Croatia, as well as US voters' rejection in November elections of Donald Trump-backed deniers of the 2020 election.
The Biden administration is also launching a joint effort with around 10 partners to counter the misuse and proliferation of spyware - which the United States fears has become a growing tool of China as its technological clout increases.
The summit will work on "holding Russia accountable for its unjust and unprovoked war against Ukraine, showing that democracies are strong and resolved," Biden said in brief opening remarks.
After criticism that the first summit was too US-focused, Biden tapped leaders on each continent - from South Korea, Zambia, Costa Rica and The Netherlands - as co-hosts.
Biden has come under fire from some allies for seeking to work with leaders from whom he once promised greater distance including Saudi Crown Prince Mohammed bin Salman, Egypt's military ruler turned president Fattah al-Sisi and Recep Tayyip Erdogan, who has led Turkey for two decades.
None of the three leaders were invited to the summit.
UN Secretary-General Antonio Guterres warned bluntly that the world was undergoing a "dramatic upheaval" in which democratic values are "under assault," pointing to rising attacks and restrictions on media and human rights defenders.
"Today, we see more and more despotism and less and less enlightenment," Guterres told the summit.
"History has shown time and again that autocratic leadership is not the guarantor of stability; it is a catalyst of chaos and conflict."
Tuesday, Biden voiced alarm about Israel. "Like many strong supporters of Israel I'm very concerned," Biden told reporters. "They cannot continue down this road, and I've sort of made that clear."
Israeli PM Binyamin Netanyahu, told the summit that the alliance with the United States was "unshakable" and called Biden "a friend of 40 years."
Indian Prime Minister Narendra Modi, courted by the United States as a bulwark against China, also extolled the virtues of democracy days after the opposition chief was expelled from parliament over a conviction for defaming the right-wing leader.
"Democracy is not just a structure; it is also a spirit," said Modi, whose government is also accused of a growing clampdown on media.
Rights advocates say there is little evidence the countries joining the summit have made progress on improving their democracies, and that there is no formal mechanism to hold participants to the modest commitments made at the first meeting.
"We're at an inflection point in history here when the decisions we make today are going to affect the course of our world for the next several decades," Biden said.
"Our job is to keep building on our progress, so we don't start heading in the wrong direction again -- to keep the momentum going."
This report was sourced from Reuters and Agence France-Presse.