After holding back many of its units trained and armed by the West, Ukraine is now committing them, the officials said, but it remained unclear whether a full-scale assault was taking place.
Ukraine has launched the main thrust of its counteroffensive, throwing in thousands of troops held in reserve, many of them Western-trained and equipped, two Pentagon officials said on Wednesday, hours after Russian officials reported major Ukrainian attacks in the southern Zaporizhzhia region.
A spokesman for Russia’s Defense Ministry, Igor Konashenkov, said the Ukrainians had mounted a “massive” assault with three battalions, reinforced with tanks, south of the town of Orikhiv, and then another a few miles farther south near the village of Robotyne, according to the state news agency Tass. Both were repelled, the ministry said.
Other American officials cautioned that the latest Ukrainian attack might be preparatory operations for the main thrust or perhaps just reinforcements to replenish war-weary units.
The challenge for the Ukrainians, since they began their counteroffensive in early June, has been to blast open a gap in the deep Russian defense network, and then try to pour through a much larger force.
Speaking on the condition of anonymity to discuss internal deliberations, officials at the White House and Pentagon said on Wednesday that they were watching the increased activity with keen interest, and that Ukrainian officials had told them the new operation, if successful, would last one to three weeks.
“This is the big test,” said one senior official.
Administration officials and analysts said it might be only a matter of days to assess whether the attacks might be successful. “It will be clear soon whether this attack will allow Ukraine to change the current dynamic,” said Michael Kofman, a senior fellow at the Carnegie Endowment for International Peace.
Ukrainian officials declined to confirm that the assaults took place.
The force cited by the Kremlin — three battalions, roughly up to 3,000 troops — is relatively small. A Russian occupation official describing the attack referred on the Telegram app to Ukrainian “brigades,” and in a later post to “battalions,” a major difference. A brigade typically has three to five battalions.
The United States and other Western allies have trained about 63,000 Ukrainian troops, according to the Pentagon, and have supplied more than 150 modern battle tanks, a much larger number of older tanks, hundreds of infantry fighting vehicles and thousands of other armored vehicles. All of those figures continue to rise, and much of that manpower and gear had been held in reserve until now, as Ukrainian forces fought to find — or create — a strategic vulnerability they could exploit.
