ODESSA, Ukraine — After capturing the strategic city of Kherson, Russian forces pushed west on Thursday, moving along the southern Black Sea coast in the direction of Odessa. They continued to lay siege to the critical port city of Mariupol in Ukraine’s east, though there was no indication that they had captured it.
After eight days of war, Russian troops deployed in Ukraine’s southern theater finally appeared to be building some momentum. But their progress has been far slower than military analysts would have expected given their massive advantages over the Ukrainian military.
For eight years, President Vladimir V. Putin of Russia has been building what amounts to a sprawling military staging area in the Crimean Peninsula, which Russia annexed in 2014. Forces stationed there should have been well equipped to charge out of their bases and seize swaths of southern Ukrainian territory the moment the order was given to invade. Russia’s near naval monopoly in the Black Sea and the Sea of Azov should have provided additional fire power to assist ground troops.
Instead, their advancement has been sluggish, beset by logistical issues and a seeming inability of commanders to coordinate disparate military forces, which if combined effectively should have easily overwhelmed Ukraine’s defenses.
“I thought along the Black Sea coast was where they would have their best success immediately because of the huge advantage of having this bridgehead in Crimea,” said Lt. Gen. Ben Hodges, the former commander of the U.S. Army in Europe.
Mariupol continued to hold out on Thursday despite a withering Russian bombardment that cut power, water and heat to the city. But the mayor, Vadym Boichenko, painted a grim picture of the Russian siege.
“Mariupol is still being shelled,” he said in a statement on Facebook. “The women, kids and elderly people are suffering.”
Despite pounding Russian artillery strikes in Kyiv, the capital, and Kharkiv, Ukraine’s second largest city, there has been very little advancement in recent days among troops stationed in the country’s north.
In the south, the campaign to seize the southern coastline was given a boost this week with the capture of Kherson, a city of 300,000 people that is an important ship building center. From there, Russian troops have been on the move in the direction of Mykolaiv, another port city on the Black Sea.
On Thursday, Mykolaiv’s mayor, Oleksandr Senkevych, said roughly 800 Russian vehicles, including a column of grad rocket launchers, was headed toward the city, which has one of Ukraine’s three largest ports, from north, east and south. As of Thursday morning, there had been no shelling inside the city. But Ukrainian forces on the city perimeter have been fired on by long-range rockets, forcing them to move positions constantly, Mr. Senkevych said.
“The city is ready for war,” Mr. Senkevych said.
But charging further down the coastline could put Russian forces in danger of stretching themselves too thinly, said Michael Kofman, the director of Russia studies at CNA, a research institute based in Arlington, Va. Already, the forces in Ukraine’s south and elsewhere appear in some instances to have outpaced logistical units, forcing them to stop and wait for fuel and other supplies.