Ukrainian troops hoist flag above building in Vysokopillya, in southern Kherson region.
Washington CNN  — 

One week into a new counteroffensive, Ukrainian forces are making gains in the south, with the ambitious goal of taking back most of the Russian-occupied region of Kherson by the end of the year, senior US officials and Ukrainian officials tell CNN.

The last week has seen the most ambitious ground assaults by the Ukrainians since the beginning of the invasion, following sustained attacks on command posts, ammunition stores, and fuel reserves far behind the front lines, according to geolocation of video and satellite imagery.

The US has observed Ukrainian forces achieve some success in attacking Russian supply lines, with the intention of cutting off and isolating Russian troops currently deployed west of the Dnipro River, according to a senior US official.

“What we’ve seen in the Kherson region first is some continued offensive operations by the Ukrainians,” Pentagon press secretary Air Force Brig. Gen. Pat Ryder told reporters. “They continue to make some forward movement. We are aware that they have retaken some villages.”

Ryder also said that the US has seen “some offensive Russian activity … near Bakhmut.”

According to Ukrainian officials, the goal is to take at least all territory north or west of the Dnipro River, including not only the city of Kherson but also Nova Kakhovka, site of an important hydroelectric plant as well as the canal that supplies Crimea with much of its water.

At the same time, Ukrainian forces have stepped up attacks in Eastern Ukraine in order to prevent Russia from shifting forces to the South to attempt to repel the Ukrainian counteroffensive there, US officials said. In recent days, Ukrainian forces have pushed towards Russian supply lines south of Kharkiv, taking several villages and towns in the process.

The current offensive in the south is broad-based – extending more than 100 miles wide – to prevent Russian units from concentrating on one point. Additionally, there has been an uptick in sabotage operations and attacks on pro-Russian officials in occupied areas.

US officials acknowledge the Ukrainian goal of recapturing Kherson by the end of 2022 is ambitious but remains possible if Ukraine continues to make progress in its current operations.

Ukrainian forces are planning for a long and brutal campaign to retake Russian-controlled territory. The current Ukrainian push is expected to extend into the Spring, with some of the attacks now intended to prepare the battlefield for planned advances over the next several months.

Ukraine has been publicly signaling for months that it intended to launch a major counteroffensive to retake territory lost to Russia in the six-month war.

And even before Ukrainian forces began increasing their artillery rocket and missile fire on the front lines in southern Ukraine, Kyiv had been actively disrupting Russian resupply efforts and command and control across the region.

In the buildup to the current Ukrainian counteroffensive, the US urged Kyiv to keep the operation limited in both its objectives and its geography to avoid getting overextended and bogged down on multiple fronts, multiple US and western officials and Ukrainian sources previously told CNN.

Those discussions involved engaging in “war-gaming” with Kyiv, the sources said – analytical exercises that were intended to help the Ukrainian forces understand what force levels they would need to muster to be successful in different scenarios.

The Ukrainians were initially considering a broader counteroffensive, but narrowed their mission to the south, in the Kherson region, in recent weeks, US and Ukrainian officials previously said.

CNN’s Paul LeBlanc, Katie Bo Lillis and Natasha Bertrand contributed to this report.