Ukrainians have reacted skeptically to a phone call between Russian President Vladimir Putin and US counterpart Donald Trump, who had sought to convince Moscow to agree on a temporary ceasefire.

Tuesday's call did not secure the ceasefire, which was endorsed by Ukraine last week, and yielded only a Russian promise to halt attacks on energy infrastructure for 30 days.

Even that scaled-back promise from Putin was met with distrust in the Ukrainian capital.

"I don't believe Putin at all, not a single word he says," said Lev Sholudko, a Kyiv resident.

An air raid alert wailed in the capital shortly after the call on Tuesday, warning of a new wave of strikes that killed one person and damaged two hospitals in Ukraine.

"You can't trust Putin at all because Russia has repeatedly shown that it does not adhere to any agreements," Sholudko said.

Ukraine had been pushing for the US-led proposal of a 30-day unconditional ceasefire. 

But Putin said that, for a wider truce to work, Ukraine must not be allowed to rearm and must halt mandatory mobilization. 

"That's unacceptable for us," answered Karyna, a 25-year old who said she was convinced Russia "will be preparing something and we have to be ready for it."

Her skepticism was shared by Veronika Zilnova, a 27-year-old social media moderator.

"We need to be constantly armed, constantly on the alert, because we have been standing up for our country for three years, and we cannot just give up, or trust anyone," Zilnova said, tearing up thinking about fallen soldiers. 

She cautioned against believing Putin but hoped that Trump was "trying to hear both sides" and could potentially "be a plus for our country."

Sholudko disagreed, saying Trump initiating a rapprochement with Moscow showed he was "Putin's man."

"The only right way out of all this is more weapons for Ukraine. This is the only guarantee that Ukraine will be an independent, strong, democratic country," he said.