In launching an offensive against the Ukrainian coastal city of Mariupol, pro-Russian separatists have selected a target of both strategic and symbolic importance in their bloody conflict with the government in Kyiv.
Located on the Azov Sea, some 100 kilometers from the rebel-held provincial capital Donetsk, Mariupol is seen as a key element of a potential land corridor from Russia to the Crimean peninsula, which the Kremlin annexed from Ukraine in March, should the city fall to the rebels.
But because Mariupol and Crimea are separated by several hundred kilometers of territory controlled by the Ukrainian government, the city's sea access and status as a temporary regional capital controlled by Kyiv could be of more significance to the separatists, analysts say.
"Every town -- especially such a big city, and quite symbolic as well -- lost by the Ukrainian government undermines the morale of the Ukrainian side and encourages the Russian rebels to go farther and farther," said Oleksiy Melnyk, a military expert from the Razumkov public policy center in Kyiv.
Ukrainian President Petro Poroshenko in June declared Mariupol the provisional capital of the Donetsk Oblast, whose official capital, the city of Donetsk, is largely controlled by rebel fighters.
Just days before rebel leader Aleksandr Zakharchenko announced the fresh offensive against Mariupol on January 24, Poroshenko said the Russian army had recently sent 2,000 troops into eastern Ukraine.
The Kremlin has repeatedly denied supporting the separatists with arms and soldiers, though officials in Moscow have conceded that Russian “volunteers” have fought alongside the rebels.
Should the separatists manage to push through to Mariupol and take control of the city, its port could provide a critical logistical lifeline for the rebels and Russian fighters battling Ukrainian forces, Melnyk added.
The Mariupol Sea Port handled 13 million metric tons of cargo -- including steel -- last year, making it Ukraine's fifth largest port in terms of freight traffic in 2014 and by far the busiest commercial marine hub on the Azov Sea, according to official government data.
"Should the rebels capture it, this would essentially deprive Ukraine of the Azov coast. Not in a geographical sense, but in an economic sense," said Aleksandr Khramchikhin, deputy director of the Moscow-based Institute of Political and Military Analysis.
The rebel offensive against Mariupol may indeed be part of a broader strategy to link Russia to Crimea, especially since there appears to be little headway in Moscow's plan to build a bridge to the peninsula across the Kerch Strait, Melnyk said.
"Now, again, it seems like this issue of creating a land corridor might become on the top of the agenda," he added.
But Khramchikhin said that while the rebels "have chances" to capture Mariupol, expanding their control through the government-held Zaporizhzhya and Kherson oblasts is likely beyond their capabilities "in the current situation."
"I think the ambitions and real possibilities of the rebels don't extend beyond their own oblasts," he said, adding that the land-corridor scenario remains "strictly theoretical."
Mariupol, which has a population of around 500,000, is also situated on important roads running from the Russian border and continuing farther into Ukraine.
It was seized by rebel fighters amid bloody skirmishes last year but retaken by Ukrainian forces in June.
The rebels advanced toward Mariupol in August and September, fighting government forces some 20 kilometers east of the city, but did not reach the port.
That push prompted some Mariupol locals at the time to train for possible "partisan" warfare against the separatists.