President Putin on Thursday ordered his armed forces to observe a unilateral 36-hour ceasefire in Ukraine this weekend for the Orthodox Christmas holiday, the first such sweeping move in the nearly 11-month-old war. Kyiv indicated it won’t follow suit.

Mr. Putin did not appear to make his ceasefire order conditional on Ukraine’s acceptance, and it wasn’t clear whether hostilities would actually halt on the 684-mile front line or elsewhere. Ukrainian officials have previously dismissed such Russian moves as playing for time to regroup their invasion forces and prepare additional attacks.

At various points during the war that began February 24, Russian authorities have ordered limited, local truces to allow civilian evacuations or other humanitarian purposes. Thursday’s order was the first time Mr. Putin has directed his troops to observe a ceasefire throughout Ukraine.

“Based on the fact that a large number of citizens professing Orthodoxy live in the combat areas, we call on the Ukrainian side to declare a ceasefire and give them the opportunity to attend services on Christmas Eve, as well as on the Day of the Nativity of Christ,” Mr. Putin’s order to his defense minister, Sergei Shoigu, published on the Kremlin’s website, said.

Mr. Putin’s order didn’t specify whether it would apply to both offensive and defensive operations. It wasn’t clear whether Russia would strike back if Ukraine kept fighting. Ukrainian officials dismissed Mr. Putin’s move.

A Ukrainian presidential adviser, Mykhailo Podolyak, tweeted that Russian forces “must leave the occupied territories — only then will it have a ‘temporary truce.’ Keep hypocrisy to yourself.” Ukraine’s National Security Council chief, Oleksiy Danilov, told Ukrainian TV: “We will not negotiate any truces with them.”

President Biden said it was “interesting” that Mr. Putin was ready to bomb hospitals, nurseries, and churches on Christmas and New Year’s before making this move. “I think he’s trying to find some oxygen,” he said, without elaborating.

Moscow could try to use Ukraine’s rejection of the short truce offer for its own propaganda purposes. 

The U.S. state department spokesman, Ned Price, said Washington had “little faith in the intentions behind this announcement,” adding that Kremlin officials “have given us no reason to take anything that they offer at face value.”

The UN spokesman, Stephane Dujarric, welcomed the move but said it “will not replace a just peace in line with the UN Charter and International law.”

Mr. Putin acted after the head of the Russian Orthodox Church, Patriarch Kirill, proposed a truce between noon Friday and midnight Saturday Moscow time. The Orthodox Church, which uses the Julian calendar, celebrates Christmas on January 7 — later than the Gregorian calendar — though some Ukrainian Christians also mark the holiday on that date.

Kirill has previously called the war part of Russia’s “metaphysical struggle” to prevent a Western liberal ideological encroachment. President Zelensky had proposed a Russian troop withdrawal earlier, before December 25, but Moscow rejected it.

Mr. Putin issued the truce order after the Turkish president, Recep Tayyip Erdogan, urged him in a phone call to implement a “unilateral cease-fire,” according to the Turkish president’s office. The Kremlin said Mr. Putin “reaffirmed Russia’s openness to a serious dialogue” with Ukrainian authorities.

Mr. Erdogan also told Mr. Zelensky later by phone that Turkey was ready to mediate a “lasting peace.” Mr. Erdogan, who has made such offers frequently, helped broker a deal allowing Ukraine to export millions of tons of grain, and has facilitated prisoner swaps.

Russia’s professed readiness for peace talks came with the usual preconditions: that “Kyiv authorities fulfill the well-known and repeatedly stated demands and recognize new territorial realities,” the Kremlin said, referring to Moscow’s insistence that Ukraine recognize Crimea and other illegally seized Ukrainian territory as parts of Russia.

Previous attempts at talks have failed over Moscow’s territorial demands because Ukraine insists Russia withdraw from occupied areas.

In the latest fighting, at least five civilians were killed and eight wounded by Russian shelling in the previous 24 hours, the deputy head of the Ukrainian presidential office, Kyrylo Tymoshenko, said.

An intense battle has left 60 percent of the eastern city of Bakhmut in ruins, the Donetsk governor, Pavlo Kyrylenko, said. Ukrainian defenders appear to be holding the Russians back.

Taking the city in the Donbas region, an expansive industrial area bordering Russia, would not only give Mr. Putin a major battlefield gain after months of setbacks, but would rupture Ukraine’s supply lines and allow Moscow’s forces to press on toward key Ukrainian strongholds in Donetsk.

In what appeared to be a move to entice more men to join the fight, the first convicts recruited for battle by the Wagner Group, a Russian private military contractor, received a promised government pardon after serving six months on the front line.

A video the state RIA Novosti news agency released showed the Wagner Group’s millionaire owner, Yevgeny Prigozhin, shaking hands with about 20 pardoned men.