TOKYO, Dec 6, 2023 (BSS/AFP) - Ukrainian President Volodymyr Zelensky will join a video summit later Wednesday with the leaders of the G7, chair Japan said, hours after unexpectedly skipping a virtual meeting with US senators.

Almost two years after Russia's invasion, signs are growing that Western support for Ukraine is fraying just as a counteroffensive struggles and as President Vladimir Putin's oil revenues rebound.

The meeting from 9:30 am EST (1430 GMT) hosted by Japanese Prime Minister Fumio Kishida will see Zelensky "join the first part", government spokesman Hirokazu Matsuno told reporters.

Besides Ukraine, the talks will cover the Middle East, support for developing countries, and artificial intelligence, a White House official said.

Zelensky unexpectedly cancelled a planned videolink appearance with US senators on Tuesday in which he was to have appealed for continued funding.

He had been expected to press them to support a Wednesday procedural vote on an emergency aid package that includes more than $60 billion for Kyiv.

Senate Majority Leader Chuck Schumer announced that Zelensky had been prevented from taking part by a "last minute" hiccup, but he pressed ahead with the briefing anyway -- only for the proceedings to turn into a war of words.

- 'Kneecap' Kyiv -

The US Congress is more divided over backing for Ukraine than it has been at any time during the nearly two-year conflict, with the country fast exhausting the military aid provided by the United States so far.

Senate Republicans are making their support for additional Ukraine funding contingent on President Joe Biden's Democrats accepting reforms to the asylum system and tightened border security -- measures the Democrats have already rejected.

The White House's budget chief warned Congress on Monday that failure to agree on fresh funds for Ukraine by the end of the year would "kneecap" Kyiv on the battlefield.

- EU summit -

Backing for Ukraine's war effort and its possible accession to the European Union are also set to be thorny topics at a summit next week of the bloc's leaders.

Hungarian Prime Minister Viktor Orban, whose ties with Putin are the closest among EU leaders, has demanded that key decisions on Ukraine be dropped from the gathering's agenda.

The recent election victory of Geert Wilders, whose far-right party wants to stop weapons deliveries to Ukraine, has also sparked worries about continued support from the Netherlands.

After a November meeting of G7 foreign ministers in Tokyo, the group said their support for Kyiv would "never waver" and that they were committed "to standing by Ukraine for as long as it takes".

It includes the United States, Japan, Germany, France, Britain, Italy and Canada as well as the European Union. Until 2014, it included Russia and was called the G8.