The intense fighting in Ukraine sparked a diplomatic row.

Like a fear of a Russia Invades Ukraine mounted, President Biden will speak to global allies Friday afternoon about Moscow’s military build-up, in an ongoing effort to deter any hostile advances on its neighbours.

While the US leader said there was “a way” to a diplomatic solution, Mr Biden also warned that Russian President Putin could launch an invasion within the next few days.

Washington and Moscow have exchanged conflicting accounts of whether Russian forces are indeed withdrawing from Ukraine’s border, with Russia insisting it has no plans to invade and dismissing US warnings as “information terrorism”. A fiery exchange of gunfire on Thursday between Russian-backed separatists and Ukrainian government forces, the most intense in months, has heightened tensions.

The separatists claimed on Thursday that they had been fired upon by Ukraine, the kind of fighting that Western officials warned Moscow could try to use to justify military action. The Ukrainian military said the shelling of a kindergarten injured three adult civilians.

The skirmish ushered in another diplomatic scramble. A White House official said Biden would hold a phone call with transatlantic leaders to “continue efforts to pursue deterrence and diplomacy.” It is not clear who will participate.

Secretary of State Antony J. Blinken on Thursday made an unscheduled visit to New York, where he told the United Nations Security Council that Moscow appeared to be setting the stage for an attack. Mr. Blinken also accepted an offer to meet with the Russian foreign minister, Sergey V. Lavrov, next weekend.

State Department spokesman Ned Price did not provide a time or location for the meeting, the second meeting of diplomats in two months, except to say it would not happen if Russia attacked Ukraine. . “If they invade in the coming days, it will make it clear that they have never been serious about diplomacy,” Price said in a statement.

Kremlin spokesman, Dmitri S. Peskov, also made an ominous assessment on Thursday. “The excessive concentration of Ukrainian forces near the lines of communication, together with provocations, can pose a terrible danger,” he said.