五角大楼一直在提供美国对俄罗斯入侵乌克兰和乌克兰抵抗努力的评估的每日更新。

以下是一名美国高级国防官员周一在第47天对记者说的一些要点:

俄罗斯新任入侵指挥官

美国评估认为，普京已经任命亚历山大·德沃尔尼科夫(Alexander Dvornikov)将军领导入侵行动。但据这位美国高级国防官员说，领导层的变化无法消除困扰俄罗斯军队的后勤和作战问题。

“他们有很高的挑战要克服，选择一名将军并不意味着他们准备取得更大的成功，”该官员说。

德沃尔尼科夫之前在乌克兰南部领导俄罗斯军队。

阿列克谢·尼科尔斯基/美联社，文件

俄罗斯总统弗拉基米尔·普京与亚历山大·德沃尔尼科夫上校在一次aw期间合影..

“他是南部军区的司令。在冲突的最初几天和几周，俄国人在南方取得的成功确实比他们在北方取得的要多。我不知道这是他选择的一个因素，”这位官员说。

这位官员指出，俄罗斯在南部的努力现在基本上停滞不前，自上周以来，在打击马里乌波尔方面没有任何进展，在Mykolayiv方面也没有取得成功。

“如果普京选择德沃尔尼科夫是因为他取得了一些成功，那也没什么，”这名官员说。

新指挥官，同样的“堕落和残暴”

这位官员说，目前还不清楚德沃尔尼科夫的选择会如何影响战斗，但他说，残酷的模式仍然是一个常数。

“很明显，俄罗斯人继续堕落和残暴，正如我们上周在火车站看到的导弹袭击，”这名官员说。

马里乌波尔的死亡和破坏也令人担忧。

“当世界其他地方看到马里乌波尔发生了什么，发生了什么，我们都做好了准备。我认为我们肯定会为一些潜在的非常非常可怕的结果做好准备，”这位官员说。

俄罗斯向顿巴斯运送军队和物资

一些从乌克兰北部地区撤出的俄罗斯部队开始向俄罗斯城市别尔哥罗德和瓦鲁基东移。一支长长的俄罗斯车队正开始从该地区向南前往顿巴斯。

“我们认为，我们所说的伊兹姆以北的这一列车辆来自别尔哥罗德/瓦鲁伊基地区，从那里向南行驶，”这名官员说。

上周，该官员表示，五角大楼评估俄罗斯将利用该地区改装和补给其营级战术小组(BTGs)，这些小组已被基辅附近和乌克兰其他地区的艰苦战斗所磨损。一些俄罗斯部队已经筋疲力尽，无力作战。

“至少在我们所知道的分组中，他们的btg战斗无效的数量不是微不足道的。那是什么意思?这意味着很多事情。这可能意味着他们没有有效执行任务所需的人力，也可能是弹药和补给。这可能是车辆，取决于BTG做什么——不是所有的都只是步兵，”该官员说。

五角大楼认为，车队仍然在伊兹伊姆以北，是为了加强和补给他们在顿巴斯的部队，提供指挥和控制单元、装甲车，可能还有直升机和步兵支援。

炮兵也是增援力量的一部分。

“我们已经看到证据表明，俄罗斯人开始加强他们在顿涅茨克西南的一些阵地。他们主要是用炮兵部队来完成的，”这位官员说。

通过空运和陆运向乌克兰提供的军事援助

该官员称，每天有8至10次航班向该地区运送军用物资，而“几乎不间断的地面车队”正在向乌克兰运送物资。

美国情报部门协助乌克兰

除了以导弹、无人驾驶飞机和小型武器的形式提供支持，美国还向乌克兰提供英特尔(intel)援助。

“我们正在向乌克兰人提供有用的情报，帮助他们自卫，”这名官员说。

没有证据表明俄罗斯在乌克兰摧毁了斯洛伐克的S-300系统

虽然五角大楼评估俄罗斯在周日的空袭中损坏了机场基础设施，但没有迹象表明俄罗斯声称的任何S-300地对空系统被摧毁。

“我们没有证据证明他们摧毁了一套S-300系统，也没有证据证明那就是斯洛伐克的系统，”这位官员说。

斯洛伐克最近把它唯一的S-300电池给了乌克兰。

美国考虑训练更多乌克兰人使用新武器

俄罗斯入侵乌克兰时，一小队在美国接受军事训练的乌克兰军队刚刚于周日回国。五角大楼利用他们的存在，对他们进行了美国援助乌克兰的爆炸弹簧刀无人机的培训。这位官员周一表示，美国正在考虑培训更多乌克兰人，可能是在美国。

“这有点像是在说，乌克兰人现在很忙，他们显然需要尽可能多的人手...去打这场战争。但据我所知，没有任何政策决定会阻止他们来美国，”这位官员说。

但是五角大楼正在考虑几种可能性。

“至于像弹簧刀这样的系统的额外培训，我们正在审查、思考和考虑一些不同的选择，以如何让更多的乌克兰人接受该系统的培训，”该官员说。“如你所知，这是少数系统，但这是他们不熟悉的新系统。”

New Russian commander, same 'depravity and brutality': Pentagon update Day 47

The Pentagon has been providing daily updates on the U.S. assessment of the Russian invasion of Ukraine and Ukraine's efforts to resist.

Here are highlights of what a senior U.S. defense official told reporters Monday on Day 47:

Russia's new invasion commander

The U.S. assesses that Putin has appointed Gen. Alexander Dvornikov to lead the invasion effort. But the change in leadership can't erase the logistical and operational problems that have plagued Russian forces, according to the senior U.S. defense official.

"They have high challenges to surmount, and the choice of a general doesn't mean that they're poised for greater success," the official said.

Dvornikov previously led Russian forces in the south of Ukraine.

"He was the commander of the southern military district. And in the early days and weeks of the conflict, the Russians did achieve more success in the south than they achieved certainly in the north. I have no idea that was a factor in his selection," the official said.

The official noted that Russian efforts in the south are now largely stalled, with no progress against Mariupol since last week, and no success advancing on Mykolayiv.

"If Mr. Putin's decision to pick Dvornikov was because he had some success, it wasn't that much," the official said.

New commander, same 'depravity and brutality'

The official said it is unclear how Dvornikov's selection could affect the fighting, but said a pattern of brutality remains a constant.

"What is clear is that the Russians continue to sink to new lows of depravity and brutality, as we saw with the missile strike on the train station last week," the official said.

The death and destruction in Mariupol is also a concern.

"We're all bracing for when the rest of the world gets to see what happens in Mariupol, what has happened. I think we're certainly bracing ourselves here for some for some potentially really, really horrible outcomes," the official said.

Russians moving troops and supplies toward Donbas

Some of the Russian units that withdrew from the northern Ukraine area are starting to move east toward the Russian cities of Belgorod and Valuyki. A long convoy of Russian vehicles is beginning to head south to Donbas from that area.

"We believe that this line of vehicles that we talked about that are north of Izium came out of the Belgorod/Valuyki region, from there to the south," the official said.

Last week, the official said the Pentagon assessed Russia would use that region to refit and resupply its battalion tactical groups (BTGs) that have been worn down by hard fighting near Kyiv and other areas of Ukraine. Some Russian units are too gutted to fight.

"At least in the grouping that we're aware of, it's not an insignificant number of their BTGs are combat ineffective. And what does that mean? It means a lot of things. It can mean that they don't have the manpower that they need to effectively conduct a mission, or it could be ammunition and supply. It could be vehicles, depending on what the BTG does -- not all of them are just infantry," the official said.

The Pentagon believes the convoy is still north of Izyim and is an effort to reenforce and resupply their forces in Donbas with command and control elements, armored vehicles, and possibly helicopter and infantry support.

Artillery is also a part of the reinforcement effort.

"We've seen evidence that the Russians are beginning to reinforce some of their positions southwest of Donetsk. They're doing that largely with artillery units," the official said.

Military aid flowing to Ukraine by air and land

Eight to 10 flights per day are bringing military supplies into the region, and "near constant convoys on the ground" are flowing materiel into Ukraine, the official said.

U.S. intelligence assisting Ukraine

In addition to providing support in the form of missiles, drones and small arms, the U.S. is also giving intel to assist Ukraine in the fight.

"We are providing good intelligence to the Ukrainians to help them with their self-defense," the official said.

No evidence Russia took out Slovakian S-300 system in Ukraine

While the Pentagon assesses Russia damaged airport infrastructure with an airstrike Sunday, there is no indication that any S-300 surface-to-air systems were destroyed, as Russia has claimed.

"We have no evidence to conclude that they destroyed an S-300 system and we have no evidence to conclude that it was in fact the Slovakian one," the official said.

Slovakia recently gave its sole S-300 battery to Ukraine.

US considering training more Ukrainians on new weapons

A small group of Ukrainian troops in the U.S. for planned military training in the U.S. when Russia invaded their country just returned home Sunday. The Pentagon took advantage of their presence to train them on the explosive Switchblade drones the U.S. is sending to aid Ukraine. The official on Monday said the U.S. is looking into training more Ukrainians, possibly in the States.

"It kind of follows that the Ukrainians are busy right now and that they obviously will want as many hands on deck there ... to fight this war. But there's been no policy decision that I'm aware of that would prevent them from coming to the United States," the official said.

But the Pentagon is considering several possibilities.

"As for additional training on systems like the Switchblade, we are reviewing and thinking about and considering a number of different options for how we could manage to get more Ukrainians trained on that system," the official said. "It's a small number of systems as you know, but it's a new system that they're not familiar with."