MOSCOW - With World Cup 2018 now firmly under way in Russia, the Kremlin indicated it was back to business Thursday, holding a new round of talks with neighboring Ukraine and hinting at movement toward a possible summit meeting with President Donald Trump as early as next month.

President Vladimir Putin spoke by phone with his Ukrainian counterpart, Petro Poroshenko, as the two leaders tried to bridge differences over the stalled Minsk peace accords aimed at curtailing violence in east Ukraine that has killed an estimated 10,000 civilians.

FILE - Ukrainian President Petro Poroshenko speaks FILE - Ukrainian President Petro Poroshenko speaks during a meeting of the country's Security and Defence Council in Kyiv, May 2, 2018. (Ukrainian Presidential Press Service) FILE - Ukrainian President Petro Poroshenko speaks during a meeting of the country's Security and Defence Council in Kyiv, May 2, 2018. (Ukrainian Presidential Press Service)

According to a statement issued by Poroshenko's press office, the Ukrainian leader pressed Putin to allow the deployment of U.N.-backed peacekeepers into the Donbass territory in east Ukraine, largely held by Russian-backed rebels, as "an important instrument in the fulfillment of Minsk."

Another pressing issue, the fate of Ukrainian filmmaker Oleg Senstov, currently serving a 20-year sentence in northern Russia on charges of carrying out a terrorist act in opposition to Russia's annexation of Crimea.

Sentsov is more than a month into a hunger strike aimed at gaining the release of about 70 Ukrainians in Russian prisons as a result of Moscow's simmering proxy war in Ukraine.

In recent days, Russia and Ukraine have moved toward an agreement to allow human rights envoys to access imprisoned nationals on both sides of the conflict, including Sentsov.

But the Russian leader has thus far ruled out a trade with Ukraine for Sentsov on grounds that he, as a resident of Crimea, is now a Russian citizen and the Kremlin has no right to interfere in court decisions.

U.S. President Donald Trump and Russia's President U.S. President Donald Trump and Russia's President Vladimir Putin talk during a photo session at the APEC Summit in Danang, Vietnam, Nov. 11, 2017. U.S. President Donald Trump and Russia's President Vladimir Putin talk during a photo session at the APEC Summit in Danang, Vietnam, Nov. 11, 2017.

Trump-Putin Summit?

Meanwhile, Kremlin officials announced that a top White House envoy is headed to Moscow to lay the groundwork for a summit as early as next month between Putin and U.S. President Donald Trump.

In his weekly call with reporters, Kremlin spokesman Dmitry Peskov, insisted neither Moscow nor Washington was ready to issue a formal statement with details but did confirm media reports that U.S. National Security Adviser John Bolton would visit Russia next week.

"As far as we know, such a visit will indeed take place. This is all we can say at the moment," said Peskov in comments carried by the Interfax news agency.

Both Trump and Putin have long expressed interest in a formal summit but the sudden push for a July meeting seems to have gained traction in the wake of what the White House argues was a successful meeting earlier this month with North Korean leader Kim Jong-Un in Singapore.

In a replay reminiscent of the scramble to arrange the North Korean summit, Bolton and Russian officials will seek to hash out logistics, including the date, time, and location as well as any potential joint communique to come out of a meeting with the Russian leader.

(Both Russian and U.S. media report Austria would be the desired host country, either before or after Trump's visit to the NATO summit in Brussels July 11.)

Trump, observers note, is hemmed in by an investigation into contacts between his presidential campaign and Russian government agents on the road to his 2016 election win.

Putin, too, has previously acknowledged that allegations of Russian interference in the U.S. elections, charges the Russian president vehemently denies, starkly limit options for a productive summit.

FILE - President Donald Trump, left, meets with Ca President Donald Trump, left, meets with Canadian Prime Minister Justin Trudeau during the G-7 summit, June 8, 2018, in Charlevoix, Canada. President Donald Trump, left, meets with Canadian Prime Minister Justin Trudeau during the G-7 summit, June 8, 2018, in Charlevoix, Canada.

The U.S. president has repeatedly seemed eager to defy both his critics and foreign policy expectations when it comes to Russia — recently even angering traditional U.S. allies at the G-7 summit in Quebec, when he argued Russia should be reinstated to the Group of Eight countries, despite being kicked out for its annexation of Crimea.

For that reason, Russian political observers suggest most Kremlin officials saw a Trump-Putin summit, in whatever form, as a win, "a priori." Relations, they note, could hardly be worse than they are now.

"For Russian foreign policy, holding a summit between Putin and Trump has become something of a fixation," writes Russian foreign policy analyst Vladimir Frolov, in The Republic, an independent online publication.

"For whatever reason, it's thought that the meeting could resolve all problems, if only the leaders could talk face to face, without intermediaries, when Trump has none of his advisors to hold him back, and he can finally make good on his campaign promise to improve relations with Russia."