US defense secretary speaks with Russian counterpart for first time since Russia invaded Ukraine - CNN

Similar to the deconfliction mechanism the US and Russia have over Syria, the idea is to avoid any miscalculation or misunderstanding that might lead to an unintentional and dangerous escalation.

But even as the Pentagon said the line was successfully tested once or twice daily, there was no communication until now at the highest levels of the US and Russian militaries.

"We have not stopped trying [to establish communications] since the last time they spoke, which is right before the invasion, so it's been a consistent effort," a senior defense official said in a briefing with reporters Friday.

But the official tempered expectations on the impact of the call, saying it wouldn't solve any "acute issues" or result in "direct change" in Russia's military actions or increasingly hostile rhetoric.

The call comes at a particularly fraught time between Russia and the West, with no clear off ramp for Russian President Vladimir Putin and the war deep into its third month.

Ukrainian Defense Minister Oleksiy Reznikov said Friday that the country was entering a long phase of the war, defying early expectations that Kyiv would collapse quickly.

"In order to win it now, we must carefully plan resources, avoid mistakes, project our strength so that the enemy, in the end, cannot stand up to us, " Reznikov said.

Despite losses that have forced Russia to retreat around the Ukrainian capital of Kyiv and near the city of Kharkiv in the northeast, Moscow has shown no outward signs of backing off.

Vladimir Chizhov, Russia's ambassador to the European Union, insisted that the Kremlin's "special military operation" remains on track, even as he acknowledged that it is "not proceeding at the speed certain people wanted in Russia."

Meanwhile, Finland and Sweden are drawing ever closer to joining NATO, and the US is poised to approve another $40 billion package in aid to Ukraine, including billions in new weapons and equipment.

Both are indications that the West does not see either this conflict or its strategic consequences dissipating quickly.

Finland's ambassador to NATO, Klaus Korhonen, told CNN that the enormous groundswell of support in his country for joining the treaty alliance was a "very drastic change in our security environment."

Russia warned that it would bolster its ground forces and air defenses near Scandinavia and more naval forces if Finland and Sweden join NATO, but the threat has done little to deter their moves toward the alliance, serving perhaps only to hasten their ascension.