WATCH: Pentagon press secretary Pat Ryder speaks on Ukraine counteroffensive

Pentagon officials are being careful not to declare a premature victory after a Ukrainian offensive forced Russian troops into a messy retreat in the north.

Watch the briefing in the player above.

Instead, military officials are looking toward the fights yet to come and laying out plans to provide Ukraine with more weapons and expand training, while warily awaiting Russia’s response to the sudden, stunning battlefield losses.

Brig. Gen. Pat Ryder, the Pentagon press secretary, said Tuesday that “We are constantly engaged in a dialog to determine what are the needs of our Ukrainian partners based on the conditions on the ground. And as we’ve seen and as evidenced by this counteroffensive, they’re using the equipment they have to great effect to change the dynamics on the battlefield.”

Ukrainian troops are piling pressure on retreating Russian forces, pressing a counteroffensive that has produced major gains and a stunning blow to Moscow’s military prestige.

As the advance continued Tuesday, Ukraine’s border guard services said the army took control of Vovchansk — a town just 3 kilometers (2 miles) from Russia seized on the first day of the war.

Russia acknowledged that it has withdrawn troops from areas in the northeastern region of Kharkiv in recent days.

READ MORE: Ukraine continues to pressure retreating Russian troops

When asked about the number of Russian troops remaining In Ukraine Ryder told reporters, “Obviously Russian forces do exist in mass in Ukraine. Certainly this week we’ve seen a number of Russian forces, especially in the northeast, in the Kharkiv region, cross over the border, back into Russia as they’ve retreated from the Ukrainian counteroffensive. But in terms of specific numbers, I’m not going to be able to provide that.”

It was not yet clear if the Ukrainian blitz could signal a turning point in the nearly seven-month war. But the country’s officials were buoyant and released footage showing their forces burning Russian flags.

Although there was widespread celebration of Ukraine’s gains over the weekend, U.S. officials know Russian President Vladimir Putin still has troops and resources to tap, and his forces still control large swaths of the east and south.

“I don’t want to speculate on what Russia might do next,” Ryder, said.

Meanwhile, the Pentagon has said the U.S. is looking at future needs, including discussions about providing more intensive combat training for larger Ukraine units, a change from current training focused on smaller teams learning to handle specific weapons.

It is also considering sending additional air defense systems, as well as lethal strike drones and more surveillance drones.

Ukraine’s launch in recent days of a much-anticipated counteroffensive – in a different part of the country from where Russian troops occupying Ukraine had massed strength to meet it – has brought on the biggest territorial changes in months in the 200-day war, launched when Putin rolled Russian forces into the neighboring country, targeting its Western-oriented government.

U.S. officials acknowledged that the U.S. provided information to help the Ukrainian counteroffensive, but declined to say how much or if Western officials helped strategize the idea to throw Russian forces off guard by calling attention to attack plans in the south, while actually plotting a more formidable campaign in the east.

READ MORE: As Ukraine military retakes territory, Russia cuts power to eastern region

“We do engage with the Ukrainians, you know, at a variety of levels. On the military side, as we’ve said previously, we do provide time-sensitive information to enable them to conduct operations and defend their homeland. I’m not going to get into the specifics of what that might look like.”

Ryder added, that the Ukrainians “should be the ones to talk about what their game plan is to secure and hold the territory that they’ve gained.”

Ukrainian forces claimed Monday to have retaken a wide band of territory and more than 20 Ukrainian settlements from Russia, pushing all the way back to the two countries’ northeastern border.

Russian soldiers were surrendering in such numbers that Ukraine was having difficulty making room for them, Ukrainian military officials said.

Still, Ukrainian leaders are still pressing for more weaponry – including fighter jets and the longer-range Army Tactical Missile System, or ATACMS, a surface-to-surface missile that the U.S. has so far declined to send.

A key question going forward will be how much more Congress and the American public are willing to spend on the war in Ukraine, which the U.S. and the West say also represents a significant threat to Europe.

It’s unclear if, or how, Ukraine fighters’ successes in recent days will affect the ongoing debate.

The White House has asked Congress to greenlight an additional $11.7 billion in aid as part of an overall government funding measure that lawmakers must approve before the end of the month.

The U.S. – the lead contributor to Ukraine’s war effort among NATO members – has poured more than $15 billion in weapons and other military support into Ukraine since January.