ROME, June 25 (Xinhua) -- This year's summit of the Group of 20 (G20) industrialized nations on June 28-29 in Osaka, Japan, will take place amid more international discord than any other in recent memory. Expert observers said there will be room for only a few key issues at center stage.

The summit will take place amid an escalating trade war between the world's two largest economies; growing political and military tensions between the United States and Iran; discord within the European Union over Brexit; the rise of populist parties; migration from Africa; and slowing economic growth.

"These are challenging times for the world and it would be a good time for the G20 to become more relevant," Ferdinando Nelli Feroci, president of Italy's Institute of International Affairs, a think tank, told Xinhua. "But there will be no way to address everything in such a short summit, where each leader will arrive with a different agenda."

Silvia Menegazzi, a political scientist focusing on international relations at Rome's LUISS University, said the trade war between the United States and China, the world's two largest economies, will likely be the central issue at the talks. Each country has increased tariffs on goods from the other country, sending ripples into markets around the world.

"Several countries will be looking for ways to calm the trade tensions between the United States and China," Menegazzi said in an interview. "It's possible that pressure on the two countries will help make a difference."

Japanese Prime Minister Shinzo Abe, the summit's host, identified free trade as one of his main priorities at the summit, along with the digital economy, environmental issues and innovation.

Tensions between the United States and Iran are heating up after Iran shot down a U.S. surveillance drone flying near Iran's coast. Trump said he had called off a counterstrike against Iran at the last minute before opting for sanctions instead. Iran is not a member of the G20, and it will not have formal representation there.

Thomas H. Wilson, an international affairs professor at the University of Zurich in Switzerland, said countries would likely lobby to calm tensions.

"A military clash between the United States and Iran could be as big a problem as the trade war between Washington and Beijing," Wilson told Xinhua. "War could begin to involve other countries with political and military consequences, and the world's energy supply would be impacted."

Nelli Feroci said Italy could play a bigger role than normal at this year's summit since the Italian government will host the event again in 2012 (Saudi Arabia will host the G20 in 2020).

"I think Italy will look to reinforce certain points that are important to it," Nelli Feroci said. "Italy and the European Union will want to be sure there will be progress to show for what they are doing. I don't think anyone wants this to be seen as an ineffective meeting."