In the space of three days, three senior Russian officials have said, without providing specifics, that Washington has not followed through.
Their comments follow an intensification of Ukraine's drone strikes deep inside Russia - including two attacks last week on a Moscow oil refinery - and a Group of Seven summit at which Ukrainian President Volodymyr Zelenskiy told Trump and other Western leaders that Kyiv was turning the tide of the war.
Moscow rejects that, and has continued heavy attacks of its own.
Ever since Trump began trying last year to end the war in Ukraine, sometimes criticising Putin but more often blaming Zelenskiy for failing to reach a deal, the Kremlin has repeatedly expressed gratitude for his efforts.
Since the Alaska summit, it has often spoken of "the spirit of Anchorage" - shorthand, analysts say, for Russia's contention that Trump is sympathetic to its central demand that Ukraine give up the whole of its Donbas region in return for a freezing of battle lines elsewhere.
The US has not spelled out what, if anything, was agreed, and allied leaders were unconvinced that Trump had achieved anything by rolling out the red carpet for Putin.
However, only a month after the summit, Trump, in a characteristic shift, suggested Ukraine could recapture all the land Russia had seized, and Moscow was soon expressing disappointment.
In the first of a flurry of high-level statements on the encounter, Kremlin aide Yuri Ushakov said on Sunday that only one side had remained committed to the understandings, "while the other side, as it now appears, has not been fully able to do its part".
On Tuesday, Foreign Minister Sergei Lavrov suggested that the summit may have been a US "ploy to buy time to rearm the Kyiv regime".
Lavrov's deputy, Sergei Ryabkov, also accused the US of departing from the "fundamental understandings" reached in Alaska, according to Interfax. It quoted him as saying, however, that dialogue with the US would continue.
"We also see Washington's line moving closer to the most rabid anti-Russian policies pursued by the US's closest European allies - namely, the UK and France," another agency, RIA, quoted Ryabkov as saying, referring to last week's G7 summit in France.
Gerhard Mangott, an Austrian analyst and veteran Putin watcher, said the shift reflected Moscow's nervousness at a "very critical situation for the Russian economy and military" in light of a surge in Ukrainian attacks inside Russia. He said Moscow believed these were being assisted by the US.
"Putin needs to give a response that is visible to the population and that demonstrates that he still has cards to play," Mangott said, predicting further military escalation and a Russian push to get Trump back onside.
Putin, speaking about the recent Ukrainian strikes, said on Tuesday that "the entire West" was working for Kyiv.
Oleg Ignatov, an analyst at the International Crisis Group, said Russia was dismayed by the absence of US mediation efforts since February, when Trump launched a war against Iran together with Israel, and Washington's attention shifted.
Russia has consistently ruled out the possibility of mediation by European governments, which have given little or no sign that they would encourage Kyiv to make major concessions.
Ignatov said Russia wanted the US side to resume diplomacy to help Russia end the war on its own terms.
"There's no structured diplomatic process, there's no deal on the table, there's actually nothing," Ignatov said.
"The Russians are very disappointed about this, they really want the Americans to engage."
