Russia changed up its latest barrage, likely to try to better break through Ukraine's air defenses, war analysts say

• Russia switched up the composition of its latest large-scale strike, likely to stress Ukraine's air defenses.
• Ukraine took note of cruise and ballistic missiles but no one-way attack drones. Decoys were also used, Ukraine said.

In its most recent massive barrage on Ukraine, Russia changed up its strike package from previous attacks.

The changes to strike composition have two possible explanations, war analysts said: To preserve certain forces for future strikes and to see how Ukraine's air defenses respond to different threats and get better at penetrating them.

From late Tuesday night into early Wednesday morning, the Russians conducted a series of missile strikes against Ukraine. The size was comparable to that of recent barrages, but Ukraine said the mix of what assets were included in the attack was different.

The General Staff of the Armed Forces of Ukraine reported that Russia fired four S-300/S-400 ground-to-air missiles, 15 Kh-101/555/55 cruise missiles, eight Kh-22 cruise missiles, 12 Iskander ballistic missiles, and five Kh-59/Kh-31 missiles towards areas such as Kharkiv and Kyiv. It said that they shot down all of the Kh-101/555/55s, five of the 12 Iskanders, and two Kh-59s. The others breached Ukrainian defenses.

Some missiles, like the wildly inaccurate Kh-22 anti-ship missile, are already a challenge, but there's more to the story. The Institute for the Study of War, a Washington DC-based think tank, said footage posted by a Russian source on Tuesday appeared to show a missile releasing decoy flares, something that's been documented before.

The attack notably didn't include any of the Shahed-136/131 drones, which Russia has regularly launched in its strikes in an effort to overwhelm Ukraine's air defenses. The Shaheds, which Russia is now also producing domestically rather than sourcing them solely from Iran, have often been included in the large attacks, making their absence notable.

ISW said "this strike package may have utilized decoys in place of Shahed drones in order to experiment with the effectiveness of using such decoys and preserving Shaheds for other purposes."

Another aspect of this attack is what it says about Ukraine's ability to defend itself. Ukraine is equipped with US-provided Patriot batteries and other advanced Western air defenses and has proven quite capable at defeating Russian attacks, but it's unclear if that will continue to be the case.

"Ukrainian forces appear to have recently adapted to new Russian strike packages," ISW noted, "and Russian forces are likely continuing to experiment with new strike packages with different means of penetrating Ukrainian air defenses and forcing Ukraine to deploy air defense systems to certain locations." It's an approach that strains Ukrainian air defenses.

Russian efforts to see where it can poke holes in Ukraine's air defense come after it apparently rebuilt its precision-guided munitions stockpiles and ramped up strikes. Between December 29 and January 2, Moscow's forces launched 500 missiles and drones at Ukraine, killing dozens of people and injuring many more.

Meanwhile, Russian ground forces continue to make small, incremental gains on the battlefield, gradually squeezing around Avdiivka, located in southeastern Ukraine just west of occupied Donetsk, where they've been throwing waves of troops for the past few months with limited progress.