Russia-Ukraine updates: Russian missiles hit close to nuclear reactors: IAEA director

U.S. Secretary of State Antony Blinken is set to appeal to G20 countries to put pressure on Russia to make it support the U.N. initiative on unblocking the sea lanes for Ukraine and allow grain exports, according to local media reports.

"G20 countries should hold Russia accountable and insist that it supports ongoing U.N. efforts to reopen the sea lanes for grain delivery," said Ramin Toloui, assistant secretary of state for economic and business affairs.

Toloui referred to a U.N. campaign aiming to expedite Ukrainian and Russian exports of harvest and fertilizer to global markets.

Around 22 million tons of grain remain blocked in Ukrainian ports due to the threat of Russian attacks, Ukrainian President Volodymyr Zelenskyy said on Monday.

Ukraine is in active negotiations with Turkey and the U.N. to solve the grain export stalemate, Zelenskyy added.

Blinken is also expected to once again warn China against backing Russia's military campaign in Ukraine.

"[The upcoming G20 summit] will be another opportunity ... to convey our expectations about what we would expect China to do and not to do in the context of Ukraine," the top U.S. diplomat for East Asia, Daniel Kritenbrink, said.

-ABC News' Edward Szekeres, Yuriy Zaliznyak, Max Uzol and Nataliia Kushnir

Russia's main objective in its invasion of Ukraine is still regime change in Kyiv and the dismantling of Ukrainian sovereignty, Russian Security Council Secretary Nikolai Patrushev suggested in a speech on Tuesday.

Patrushev said the Russian “military operation” in Ukraine will continue until Russia achieves its goals of protecting civilians from “genocide,” “denazifying” and demilitarizing Ukraine, according to the Institute for the Study of War (ISW).

The Russian official added that Ukraine must remain permanently neutral between Russia and NATO. Petrushev's remarks nearly mirrored the goals Russian President Vladimir Putin announced at the onset of the war to justify the military invasion.

Patrushev, a close Putin ally, repeated the Russian President's stated ambitions despite Russia's military setbacks in Ukraine and previous hints at a reduction in war aims following those defeats, the ISW pointed out.

Patrushev's explicit restatement of Putin's initial objectives “strongly indicates” that Russia does not consider its recent territorial gains in the Luhansk region to be sufficient, the ISW experts said.

Russia “has significant territorial aspirations beyond the Donbas” and “is preparing for a protracted war with the intention of taking much larger portions of Ukraine,” the observers added.

Patrushev's comments dampened hopes for a “compromise ceasefire or even peace based on limited additional Russian territorial gains,” the experts concluded.

-ABC News' Edward Szekeres, Yuriy Zaliznyak, Max Uzol and Nataliia Kushnir

The town of Sloviansk in Donetsk Oblast will likely become the next "key" battleground in Russia's push to seize the Donbas region of eastern Ukraine, the U.K. Ministry of Defense said Wednesday in an intelligence update.

"Russian forces from the Eastern and Western Groups of Forces are likely now around 16 km north from the town of Sloviansk," the ministry said. "With the town also under threat from the Central and Southern Groups of Forces, there is a realistic possibility that the battle for Sloviansk will be the next key contest in the struggle for the Donbas."

In the meantime, Russian forces likely continue to consolidate control over the town of Lysychansk and the wider Luhansk Oblast, about 45 miles east of Sloviansk.

"To the north, it has committed most of the remaining available units from the Eastern and Western Groups of Forces to the Izium axis," the ministry added. "Over the last week, Russian forces have likely advanced up to another 5 km down the E40 main road from Izium, in the face of extremely determined Ukrainian resistance."

NATO announced on Monday it has concluded negotiations with Sweden and Finland on their accession to the organization.

"Finland and Sweden have completed accession negotiations at the NATO headquarters in Brussels, as agreed last week by the leaders of the countries at the summit in Madrid,” a NATO press release said.

“Both countries have officially confirmed their desire and ability to fulfill their political, legal and military obligations as NATO members," the NATO press service added.

The countries will sign their accession protocols on Tuesday. All member countries will then have to ratify the documents according to their national laws.

Finland and Sweden jointly submitted applications to join NATO on May 18, ending decades of neutrality in the face of Russia's invasion of Ukraine.

-ABC News' Edward Szekeres, Yuriy Zaliznyak, Max Uzol and Nataliia Kushnir