U.S. President Donald Trump and his Russian counterpart Vladimir Putin agreed in a phone call on Tuesday that the peace in Ukraine "will begin with an energy and infrastructure ceasefire."

Meanwhile, they agreed to "immediately" launch technical negotiations on the implementation of a maritime ceasefire in the Black Sea, as well as on the full ceasefire and permanent peace in Ukraine, the White House said in a statement.

"These negotiations will begin immediately in the Middle East," said the statement, noting the two leaders agreed that the three-year Ukraine conflict needs to end with a lasting peace.

The two leaders stressed the need for improved U.S.-Russia relations, said the statement. Further details are not immediately available, but U.S. media outlets, citing Russian sources, said they spoke in favor of normalizing relations between the two countries.

It is not immediately clear the response of Ukraine to the limited and phrased ceasefire plan. Kiev has said it is ready to accept the 30-day truce proposed by Trump.

Ahead of the phone talk, Trump said, "Many elements of a Final Agreement have been agreed to, but much remains."

The mess over Ukraine "will almost certainly not be resolved in a phone call, if at all," an analyst with the Fox News said.