The IOW report says that Russia launched offensives northwest of Sloviansk and southwest of the city of Donetsk, a key target for Moscow's forces.
Russian Defense Minister Sergei Shoigu ordered military units across Ukraine to increase operations to prevent strikes on parts of the country occupied by Russia, the Defense Ministry said in a statement on its website on Saturday.
The ministry said Shoigu "has given the necessary instructions to expand the activities of the army groups in all directions of attack."
The IOW report cited the Ukrainian military's general staff as having said that Kyiv's forces repelled a Russian assault on the town of Bohorodychne. The report said Ukrainian footage of a Russian mobile unit being destroyed indicated that Russian troops were trying to make progress near the town.
It also said Russian forces appeared to be trying to advance towards the town of Siversk and the Bakhmut-Lysychansk highway.
The report speculated that the Russians had resumed their offensive too early, under pressure to retain momentum.
"The Russian military seems to feel continuous pressure to resume and continue offensive operations before it can reasonably have rebuilt sufficient combat power to achieve decisive effects — at a reasonable cost to itself, however.
"The resuming Russian offensive may therefore fluctuate or even stall for some time," the report said.
Here are the other main headlines from the war in Ukraine on Saturday, July 16.
Ukraine voices concern over Zaporizhia nuclear plant – DW's Nick Spicer reports
Ukraine's defenses hold strong
An assessment from the UK's Ministry of Defence appeared to confirm the IOW summary, with reports of fighting in the same areas.
The ministry added that Ukrainian defense forces had successfully repulsed Russian attacks since Lysychansk was ceded. It said Ukrainian troops had been bolstered by having a shorter and straighter defensive line to guard.
"This has allowed for the concentration of force and fires against reduced Russian attacks and has been instrumental in reducing Russia's momentum," the ministry said.
Russia hits cities and towns across Ukraine, killing 17
Russia stepped up its assault on cities and towns across Ukraine, with Ukrainian officials announcing the deaths of 17 civilians.
Sergei Shoigu, Russia's Minister of Defense, gave an order "to further intensify the actions of units in all operational areas," the ministry said.
Ukraine's atomic energy agency Energoatom said Russia was storing weapons at the Zaporizhzhia nuclear power plant, Europe's largest, to shell the surrounding regions of Nikopol and Dnipro.
Energoatom president Petro Kotin called the situation at the plant "extremely tense" with 500 Russian soldiers controlling the facility.
Russian strike kills three in Kharkiv region
A Russian strike was reported to have hit the northeastern Ukrainian town of Chuhuiv, in the Kharkiv region, killing three people and wounding another three.
The attack reportedly damaged a residential building, a school, and a shop.
In a message on the online platform Telegram, Governor Oleh Synehubov said rescuers were searching through the rubble.
Gazprom says no sign of turbine
The Russian gas supplier Gazprom said Saturday it had asked German engineering company Siemens for details about the return of a turbine to ensure the delivery of gas from the Nord Stream pipeline to Europe.
Canada, where the turbine is being repaired, last week issued a waiver that would exempt it from sanctions imposed on Russia by Western nations.
Despite the waiver, Gazprom has said it does not know if the turbine — which is used at a compressor station for Nord Stream 1 — will be returned.
Gazprom is conducting maintenance on the pipeline over a 10-day period and has stopped delivering gas through the conduit, which runs beneath the Baltic Sea
There are fears that Moscow could use the annual work on the pipeline — which was scheduled well in advance — to shut down gas in response to Western sanctions over Russia's war in Ukraine.
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Russian President Vladimir Putin removed his longtime ally Dmitry Rogozin from the top post at Roscosmos, the Russian space agency. No reasons were given for the shakeup. Some Russian media speculated that Rogozin, a strong supporter of the Kremlin, could be tasked with overseeing Russian-controlled territories in eastern and southern Ukraine.