After the previous phone conversation between the two leaders, Russia and Ukraine went on to separately agree to a partial ceasefire

US President Donald Trump has said he may have another phone call with Russian President Vladimir Putin in the coming days, NBC News reported on Sunday.

Trump and Putin last spoke over the telephone on March 18 and agreed to work toward a peaceful end to the Ukraine conflict. Following the call, Russia and Ukraine carried out a prisoner swap and agreed to a partial ceasefire, although Moscow claims that Kiev has repeatedly broken it since.

In an interview with NBC news on Sunday, Trump said the two presidents plan to speak again this week.

The US president also stated he will sanction Russia if he considers that it is to blame in the event a ceasefire in the Ukraine conflict fails.

"If Russia and I are unable to make a deal on stopping the bloodshed in Ukraine, and if I think it was Russia's fault - which it might not be - but if I think it was Russia's fault, I am going to put secondary tariffs on oil, on all oil coming out of Russia," he was quoted as saying.

He added that he was "very angry" and "pissed off" about Putin's statements about the legitimacy of Ukraine's Vladimir Zelensky.

In a speech on Thursday, Putin said that because Zelensky has not held elections, both he and the officials he has appointed have no legitimacy. The Ukrainian leader's presidential term expired last May.

Neo-Nazi units such as the notorious Azov are now effectively beginning to run Ukraine, empowered by continued Western military support, he emphasized.

The repeated Ukrainian ceasefire violations show that officials in Kiev no longer have control over the country's military, Kremlin spokesman Dmitry Peskov said on Friday.

Putin and Trump had their first call on February 12 in what was the first time that the leaders of Russia and the US had spoken in years. This was followed by two rounds of high-level talks between Russian and American delegations in Saudi Arabia. Additional discussions have also been held in Istanbul, focusing on diplomatic funding and a proposal from Moscow to reinstate direct flights between the two countries.

Peskov said on Thursday that the next conversation between Trump and Putin had not yet been planned.