WASHINGTON (AP) — For days, a massive Russian military convoy has sat, largely stalled about 15 miles (25 kilometers) outside Kyiv, the Ukrainian capital, which is believed to be the central target of Moscow’s war.

Eight days into the war, the expanse of Russian supply trucks, troops and weapons has been plagued with fuel and food shortages and logistical challenges, including weather and mud. Ukrainian troops have managed to attack and incapacitate some vehicles at the front, creating a traffic jam, but the Russians have largely shielded the convoy from attack by air, according to Western officials and analysts.

The convoy’s lack of measurable progress has triggered questions about the short- and long-term implications and what it says about Russia’s war planning. But will it affect the war’s outcome?

Mason Clark, a Russia analyst at the Institute for the Study of War, says the convoy saga may be emblematic of shortcomings in the Russian army, which is relatively inexperienced in the execution of large-scale operations that combine air, ground and naval forces. But it is unlikely to prevent Russia from prevailing against the outgunned and outnumbered Ukrainian defenders.

“Eventually the Russians will be able to quite simply wear down Ukrainian forces,” and take Kyiv, Clark said.

A look at what’s known about the convoy:

WHERE IS IT AND WHAT HAS HAPPENED?

The convoy, which stretches for as much as 65 kilometers (40 miles) from near Prybisk in the north to the southern end near the Antonov airport, was moving steadily south at the onset of the war. But this week, progress appeared to all but stop.

Reports immediately centered on fuel and food shortages. And, a senior U.S. defense official said Ukrainian troops have been targeting the convoy with ground fire, including shoulder-fired Javelin anti-tank missiles provided by Western countries. The most significant impact of those attacks is that they struck vehicles at the front of the convoy, essentially creating a roadblock.

In addition, the muddy ground has made it difficult for the Russians to go off-road to make more progress along other routes. Photos and videos show vehicles stuck in the mud.

John Kirby, the Pentagon press secretary, said U.S. officials assess that the convoy, as well as the broader Russian thrust toward Kyiv from the north, is largely stalled. He said the Russians appear to be regrouping and reassessing the reasons for their slow progress, “and how to make up for lost time.” He said they likely did not anticipate such problems or the extent of the Ukrainian resistance.

A SITTING DUCK?

The most frequent question has been why doesn’t the Ukraine military decimate it, as it sits on the highways.

Such a long string of military vehicles in relatively open terrain would normally be vulnerable to air attack. But any Ukrainian attacks on the convoy may be limited because officials believe it contains air defense systems and may be shielded by screening forces to ward off ground attackers.

While the Ukrainian military has hit vehicles in the front and in other sporadic locations, it is likely too risky to put manned aircraft in the area to take it out with larger weapons, which also could be met with defensive strikes. And Ukraine’s military has been focused on defending the major cities that are under siege and in danger of being overtaken.

DOES THIS SIGNAL SERIOUS PROBLEMS FOR RUSSIA’S OFFENSIVE?

U.S. officials caution against any sweeping conclusions that the convoy problem signals a debilitating setback for the Russians. While it clearly has stalled the Russian assault on Kyiv for now, officials believe Russia has so much military combat power in Ukraine that it will adjust, compensate and overcome such setbacks.

Observers say Russia has clearly been frustrated by persistent logistical and supply problems, with troops running out of food and vehicles running out of fuel.

Clark said some portion of the fuel-truck segment of the convoy ran low on fuel, ironically, “which tells you the state of Russian logistics on this line of advance.”

It is also possible, officials say, that part of the reason for the stalled progress is that Russian commanders are deliberately pausing to reassess and reset, allowing time to get more supplies at the ready before beginning a further advance on Kyiv.

Observers also note that in other places — largely in the south — Russian troops are having more success. They announced the capture of the southern city of Kherson, a vital Black Sea port of 280,000, and local Ukrainian officials confirmed the takeover of the government headquarters there. And they were gaining ground in their effort to move into Mariupol. a strategic port on the Azov Sea.

Still, the extent — and days-long length — of the convoy’s problems do raise larger issues about whether the Russians adequately prepared for the attack, despite positioning troops around Ukraine for months before actually moving in. A critical — and many would say No. 1 — tenet for any ground campaign is to ensure that troops have the supplies, weapons and basics such as food, water and fuel, they need to move forward to their objective.

On Thursday, French President Emmanuel Macron spoke for 90 minutes with Russian President Vladimir Putin, who told him that military operations in Ukraine are “going according to plan,” an official in the French president’s office said.

But, Russia’s inability to keep its troops supplied has raised eyebrows in the Pentagon, where officials note that it has been years since Moscow’s military has been involved in this type of ground war. And they say it’s hard to tell if this was a failure to properly plan or a collapse in the Russian military’s execution of the plan.

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