HANGZHOU - The ongoing Group of 20 (G20) Summit hosted here by China presents an opportunity to boost international cooperation and promote global economic growth, European Union (EU) leaders said Sunday.

"There could not be a more dynamic place than Hangzhou in China to inspire our discussion on how to reinforce global cooperation," said European Council President Donald Tusk at a joint press conference with European Commission President Jean-Claude Juncker.

The EU welcomes China's presidency of the G20 this year and is looking forward to having a successful summit in Hangzhou, he added.

Juncker, for his part, congratulated China for doing "an excellent job" in hosting the 11th G20 summit, saying that it is an opportunity to restore confidence and promote the world economy.

The EU leaders also dwelled upon the climate change issue, noting that G20 members have an important role to play in tackling the global challenge.

"With major emitters around the table, we need to make sure that it is our common priority to implement the Paris Agreement early and in a robust manner," Tusk said, referring to the landmark deal reached in the French capital in December 2015.

The EU, he added, is happy to see that the United States and China have ratified the accord, which charts the course for post-2020 global cooperation against climate change.

Chinese President Xi Jinping and US President Barack Obama on Saturday handed over their countries' legal instruments of joining the Paris Agreement to UN Secretary-General Ban Ki-moon.

Xi said that climate change concerns the well-being and future of humanity and the handover marks a new and solemn commitment of the Chinese government.

At the press conference, the EU leaders also talked about the European refugee crisis and terrorism among other issues, calling for concerted efforts to address the root causes of those threats.

Tusk and Junker are among a constellation of national leaders and international organization chiefs who have gathered in Hangzhou for this year's G20 summit, which opened Sunday with the theme of "Toward an Innovative, Invigorated, Interconnected and Inclusive World Economy."