BERLIN -- German and European Union leaders gathered experts Tuesday to start work on what Germany's chancellor described as a "new Marshall Plan" for the rebuilding of Ukraine.

The Marshall Plan was a U.S.-sponsored initiative that helped revive western European economies after the Second World War. German Chancellor Olaf Scholz, whose country currently chairs the Group of Seven industrial powers, first announced plans for the one-day conference in the summer.

Kyiv's backers need to discuss already "how to ensure and how to sustain the financing of the recovery, reconstruction and modernization of Ukraine for years and decades to come," said Scholz, who co-hosted the meeting with European Commission President Ursula von der Leyen.

He said he's looking at "nothing less than creating a new Marshall Plan for the 21st century, a generational task that must begin now."

Von der Leyen said the World Bank puts the cost of damage to Ukraine so far at 350 billion euros (US$345 billion). The EU decided in June to make Ukraine a candidate to join the bloc, and needs "to firmly embed Ukraine's reconstruction efforts as part of its path toward the European Union," she said.

In addition to longer-term help and short-term assistance with its regular budget, "Ukraine needs fast rehabilitation right now as we speak," as Russia targets Ukrainian electricity and other infrastructure ahead of the onset of the winter, von der Leyen said. She called those attacks "pure acts of terror."

Ukrainian President Volodymyr Zelenskyy emphasized that point in a video address from Kyiv. He told the Berlin conference participants that Ukraine has a $17 billion "fast recovery" plan to repair damage to hospitals, schools, transportation and energy infrastructure, and other structures.

"As of now, we haven't received a single cent for the implementation of the fast recovery plan," he said, speaking through an interpreter.

Scholz underlined Germany's commitment to keep supplying Ukraine with weapons, including air-defence systems, as long as they are needed.

"The best reconstruction is the reconstruction that does not have to happen at all because Ukrainian cities and power stations are protected from Russian bombs, drones and missiles," he said.

"We do not yet know when this war will end, but end it will," the German leader said. "From our own historical experience, we also know that reconstruction is always possible and that it is never too soon to tackle this task."

Zelenskyy called for reimbursement for damages using seized Russian assets, a point that Polish Prime Minister Mateusz Morawiecki underlined.

"There is a huge pot of gold to be taken and dedicated for Ukraine's reconstruction, which is Russian assets -- assets of the Russian Federation and Russian oligarchs," Morawiecki said. "Freezing means really not too much. ... They have to be confiscated."

Von der Leyen said that is the aim, but sounded a note of caution. "The will is there, but legally it is not trivial; there's a lot of work still in it," she said. "We insist on the rule of law. ... This process has to be legally sound."

Scholz and von der Leyen invited the leaders of the International Monetary Fund, the Organization for Economic Cooperation and Development, the European Investment Bank, the European Bank for Reconstruction and Development, the UN Development Program and others on Tuesday.

Ukrainian Prime Minister Denys Shmyhal said he hopes a "financial co-ordination platform" for efforts to help his country will be set up by the end of this year.

"We have no time to waste. The scale of destruction is staggering," von der Leyen said. "We need all hands on deck -- the G7, the European Union, Europe; strong partners like the United States, Canada, Japan, the U.K., South Korea, Australia, New Zealand and many, many more."