In February, three Russian sources told Reuters that the United States had rejected Putin's previous suggestion of a ceasefire to prevent war from escalating.
In the absence of a ceasefire, Putin is seeking to seize as much territory as possible to increase pressure on Ukraine, while also trying to exploit unexpected opportunities to gain more territory, three sources said.
Russian forces control about 18 percent of Ukraine and this month advanced into the region northeast of Kharkiv.
Putin is confident that Russia's larger population compared to Ukraine will result in a better manpower even without mobilisation, and that those who join will receive unusually generous pay packages.
“Russia will continue to make efforts,” said a source who has worked with Putin.
Putin will gradually annex the territories unless Zelenskyy proposes to halt them, the source said, adding that the Russian leader had expressed the view to his colleagues that the West would not provide enough arms, which would demoralise Ukraine.
US and European leaders have said they will stand with Ukraine until its security sovereignty is guaranteed. NATO countries and allies say they are trying to speed up arms deliveries.
In response to a question about arms supplies, the State Department said, “Russia can end the war at any time by withdrawing its forces from Ukraine rather than continuing its brutal daily assault on Ukrainian cities, ports, and people.”
All five sources said Putin has told advisers he has no intention of moving on NATO territory, reflecting his public comments on the matter. Two of the sources cited Russian concerns about growing threats including nuclear escalation with the West over the Ukraine standoff.
The State Department said the United States had not changed its nuclear posture, nor had it seen any indications that Russia was preparing to use a nuclear weapon.
“We are constantly monitoring the strategic environment and remain prepared,” the spokesperson said.