BUCHAREST, Romania — Officials of the North Atlantic Treaty Organization on Tuesday stressed their commitment to eventually allowing Ukraine to become a member of the military alliance. But they spent the first day of a two-day summit focused on a more immediate concern: helping the nation rebuild an electrical grid crippled by relentless Russian airstrikes.
Over the past eight months, the United States and its allies have poured in billions in aid to help Ukraine fend off the Russian invasion, largely in the form of weaponry. Now, with millions of Ukrainians facing the prospect of a winter without heat, discussion is focusing as much on transformers, circuit breakers and surge arresters as on tanks, artillery and air-defense systems.
On Tuesday, American officials pledged to give Ukraine $53 million to repair the electrical grid, and sought to rally other allies to make similar offers.
The aid commitment came as diplomats from more than 30 nations gathered in Bucharest, Romania, where the NATO secretary-general made clear that the alliance might one day expand to include Ukraine — a stance opposed by President Vladimir V. Putin of Russia.
“NATO’s door is open,” said Jens Stoltenberg, the secretary general of NATO.
But for the present, he said, the war has to be the focus.
“NATO will continue to stand for Ukraine as long as it takes,” Mr. Stoltenberg said. “We will not back down.”
Western officials say the Ukrainian reconstruction campaign needs to be considered a second front in the war. The American pledge that was made on Tuesday came from Secretary of State Antony J. Blinken at a meeting of Group of 7 nations and a few other partner countries, on the sidelines of a two-day conclave of NATO foreign ministers.
In Ukraine, as the temperatures drop, millions have been living without power and water.
Russia’s military has sent wave after wave of missiles and drones to hit the country’s transmission grid, including high-voltage transformer stations, which are more vulnerable than power plants. One senior American official estimated that 25 to 30 percent of Ukraine’s energy infrastructure had been damaged, though Ukrainian officials have put the figure much higher in recent days.
In April, not long after Russian troops swept into Ukraine, American officials marshaled dozens of allies to furnish Ukraine with long-term military aid, and organized the countries into the Ukraine Defense Contact Group.
Now U.S. officials want to do much the same on the infrastructure front.
The Americans are organizing a working group to help Ukraine repair energy equipment and to better defend its power plants and grid from attack. The talks began early this month at a meeting of foreign ministers of the Group of 7 nations in Münster, Germany.
The energy “contact group” is centered on those nations and their close partners, and is expected to meet again next month in Paris.
The $53 million announced on Tuesday is to be used to buy a range of equipment, including distribution transformers and circuit breakers, the State Department said. The U.S. government plans to buy the equipment and transfer it to Ukraine, focusing first on what can be shipped there fastest, a senior agency official said. The Biden administration has already identified $30 million of equipment that can be sent, including from Department of Energy stocks, the official said.
“This equipment will be rapidly delivered to Ukraine on an emergency basis to help Ukrainians persevere through the winter,” the State Department said in a statement.
The department said the $53 million the United States pledged is in addition to $55 million in emergency energy sector support for generators and other equipment it already promised to Ukraine.
Dmytro Kuleba, the foreign minister of Ukraine, told reporters in Bucharest, where he was also attending the NATO meeting, that both the power equipment and the means to protect the infrastructure were important and urgently needed.
“When we have transformers and generators, we can restore our system, our energy grid and provide people with decent living conditions, which President Putin is trying to deprive them of,” he said. “When we have air defense systems, we will be able to protect this infrastructure from the next Russian missile strikes, and they are definitely to come. Unfortunately, this is the reality that we have to prepare for.”
American and European officials say Moscow is trying to break the morale of Ukrainians by depriving them of basic utilities over the winter. It embraced the tactic after the Russian military began suffering major setbacks in recent months, including being forced to retreat from the southern city of Kherson and the Kharkiv region in the northeast.
NATO countries have so far provided some $40 billion in weaponry to Ukraine, roughly the size of France’s annual defense budget. But Ukraine has been tearing through stockpiles, setting off a scramble to supply the country with what it needs while also replenishing NATO members’ own arsenals. Many Western-made howitzers are breaking because of heavy use by Ukrainian troops.
Officials also discussed how to better protect the NATO member nations that are closest to Ukraine, including Poland and Romania, from any potential spillover from the conflict. The topic took on a renewed sense of urgency this month when a missile that NATO leaders said appeared to have been fired by Ukraine’s air defense systems killed two civilians in southeastern Poland.
It was at a NATO summit also in Bucharest, in 2008, that President George W. Bush forced through a controversial promise that Ukraine and Georgia would join the alliance some day, though when was not clear. Germany and France objected, arguing that the promise was an unnecessary provocation to Russia.
Four months later, Mr. Putin ordered Russian troops to invade Georgia, and some analysts have argued that Mr. Putin has been trying ever since to make sure that NATO’s vows to expand to former Soviet states prove hollow.
On Tuesday, recalling the 2008 summit meeting, Mr. Stoltenberg said: “We stand by those decisions. NATO’s door is open.”
Ukraine, however, will almost certainly not be joining the alliance anytime soon, notwithstanding its longtime ambition to to do so. Admitting a country requires unanimous consent from all NATO members, and the alliance — predicated on the doctrine of mutual defense — is highly unlikely to admit a country already at war.
The gathering Tuesday was also attended by the foreign ministers of Sweden and Finland, which both applied for NATO membership after Mr. Putin ordered the invasion of Ukraine in February.
In London on Tuesday, in a speech to British lawmakers, Ukraine’s first lady, Olena Zelenska, called on the world to hold Russia accountable for atrocities in Ukraine. She said Ukrainians had documented thousands of war crimes committed by Russia, and called for the institution of an international tribunal to prosecute them.
Repeatedly citing World War II, Ms. Zelenska recalled that 80 years ago in London, the Allies signed the declaration that became the basis for the Nuremberg trials, which brought many perpetrators of Nazi war crimes to justice.
“Victory is not the only thing we need,” she said. “We need justice.”
Emma Bubola contributed reporting from London.