[54] Russian forces initially captured several towns and cities,[55][56] but logistical and supply failures, stiff Ukrainian resistance, and subsequent poor morale caused the advance to stall.

[70] In the morning of 25 February, Ukraine's military said its airborne forces were fighting in the settlements of Dymer and Ivankiv, where a large amount of Russian armored vehicles had advanced.

[80] On the morning of 27 February, a large convoy of Russian vehicles more than 4.8 kilometres (3 miles) long was seen on satellite images on a road near Ivankiv heading towards Kyiv.

[98][99] After securing a breakthrough at Ivankiv on 25 February, troops from the 41st Combined Arms Army, 31st Guards Air Assault Brigade, and the Chechen 141st Motorized Regiment advanced to the nearby town of Hostomel on the same day.

[110][109] Both sides suffered heavy losses during the battle:[111] Russian forces lost over 21 light infantry fighting vehicles (IFVs) in two days;[112][108] Ukrainian intelligence claimed the 31st Guards recorded over 50 deaths.

[120] It has been reported that, on 26 February 2022, Russian paratroopers began an assault on Vasylkiv, 40 kilometres (25 mi) south of Kyiv, to capture a military airbase nearby.

[124][125][126] The New York Times cited reports by unnamed Ukrainian officials, that at least part of the attackers were sleeper agents who had bought apartments in the city the month before the invasion.

[172][173][174][175] Russian artillery began bombarding the city at the same time,[176][177] causing several civilian casualties, reportedly also wounding the mayor of Bucha, Anatoliy Fedoruk.

The 1st Brigade failed to reach a planned defensive line at Ripky and Horodnia on time, though it still managed to stall the Russian advance north of Chernihiv and began to fortify the city.

[214][218] In the early hours of 2 March, the Sumy administration claimed that about 100 Russian military vehicles, mainly tanks and armored personnel carriers (APCs), had been destroyed in the village of Byshkin [uk].

[245] In the Sumy Oblast, the Russian offensive began to stall due to Ukrainian resistance west and southwest of Trostianets, and the detonation of a bridge south of the city.

[218][246] On the same day, the Sumy Oblast territorial defense was reported to have erected roadblocks and checkpoints on some parts of the Kipti-Bachivsk highway, a major road which had been one of the main routes of the Russian invasion.

[261] The same day, Ukraine's 93rd Mechanized Brigade announced that Ukrainian artillery had destroyed a Russian column near the village of Moskovskyi Bobryk [uk].

[276] The Ukrainian General Staff claimed on 19 March that units of Russia's 1st Guards Tank Army were focused on surrounding Sumy, while preparing offensive operations in the areas of Trostianets, Okhtyrka, and Poltava.

[279][280][281] Between 11 and 12 March, the Ukrainians claimed to have destroyed a column of 80 military vehicles belonging to the 228th Motorized Rifle Regiment of the 90th Tank Division in the Chernihiv Oblast.

[290] An assessment of the offensive at this date by the Institute for the Study of War said that Russian ground forces attempting to encircle Kyiv had paused to resupply and refit their combat units, having failed in their attacks from 8 to 10 March.

[293] On 12 March, the Institute for the Study of War stated that it was likely that counterattacks by the Territorial Defense Forces of Ukraine threatened Russia's long line of communication in this theater.

[297][298][299] Russian Defense Ministry spokesman Igor Konashenkov stated that long-range high-precision missiles were used to destroy the military airfield in Vasylkiv and the "main center of radio and electronic intelligence of Ukrainian forces" in Brovary.

[311] On 17 March, Ukraine's Defense Ministry announced that Russian forces had made "no significant advances around Kyiv in the past 24–48 hours" and had resorted to "chaotic" shelling.

[314] On 20 March, Russian missiles struck a number of areas in the capital and what Russia described as a "Ukrainian special forces training center" in Zhytomyr Oblast.

[316] Unable to achieve a quick victory in Kyiv, Russian forces switched strategies and began using standoff weapons, indiscriminate bombing, and siege warfare.

[324] On 24 March, the International Atomic Energy Agency (IAEA) said that Russian shelling on Slavutych prevented personnel from rotating to and from the Chernobyl nuclear plant.

[327] A British Ministry of Defence intelligence assessment reported that, as Russian forces were falling back on overextended supply lines, Ukraine recaptured towns and defensive positions up to 35 kilometers (25 miles) east of Kyiv.

[331] Following several days of Ukrainian artillery shelling and drone strikes, Trostianets was abandoned by Russian troops over the night of 25-26 March, and Ukraine's 93rd Mechanized Brigade retook the city on the 26th.

According to the Britain's Defense Ministry, "Russian forces continue to hold positions to the east and west of Kyiv despite the withdrawal of a limited number of units" and projected that heavy fighting would likely take place in the suburbs of the city in coming days.

[344][345] After several weeks of attacks, and a month under siege, Ukrainian forces managed to break the encirclement of Chernihiv on 31 March by recapturing a main road connecting Kyiv with the regional capital.

Ivankiv was also captured by 1 April, as Ukrainian forces advanced from Zhytomyr Oblast, and some reports suggested that they had conducted counterattacks in Dytiatky and Orane [uk].

Zelenskyy warned for "a potentially catastrophic situation for civilians" due to mines left by Russian forces around "homes, abandoned equipment and even the bodies of those killed".

The Institute for the Study of War also said that some of the Russian units that were pulled back to Belarus and western Russia would "remain combat ineffective for a protracted period".

[368] As the second phase of the invasion began, Kyiv was left generally free from attack apart from isolated missile strikes, one of which occurred during the 28 April 2022 visit of UN Secretary-General António Guterres, who met with Zelenskyy to discuss the fate of survivors at the siege of Mariupol.