KHARKIV, Ukraine >> As Russian missiles struck a key Ukrainian city, Russian President Vladimir Putin expanded a fast-track procedure for obtaining Russian citizenship to all Ukrainians today, another effort to strengthen Moscow’s influence over war-torn Ukraine.

Until recently, only residents of Ukraine’s separatist eastern Donetsk and Luhansk regions, as well as residents of the southern Zaporizhzhia and the Kherson regions, large parts of which are now under Russian control, were eligible to apply for the simplified passport procedure.

Ukrainian Foreign Minister Dmytro Klueba said Putin’s signing of a passport decree, which also applies to stateless residents in Ukraine, was an example of his “predatory appetites.”

“Russia is using the simplified procedure for issuing passports to tighten the noose around the necks of residents of the temporarily occupied territories of our state, forcing them to participate in the criminal activities of the occupying administrations and the Russian army of aggression,” Ukraine’s Foreign Ministry added in a statement.

Between 2019, when the procedure was introduced for the residents of Donetsk and Luhansk, and this year, more than 720,000 people living in the rebel-held areas in the two regions — about 18% of the population — have received Russian passports.

In late May, three months after Russia invaded Ukraine, the fast-track procedure was also offered to residents of the Zaporizhzhia and Kherson regions.

The Russian passport move appears to be part of Putin’s political influence strategy, which has also involved introduction of the Russian ruble in occupied territory in Ukraine and could eventually result in the annexation of more Ukrainian territory into the Russian Federation. Russia already annexed Ukraine’s Crimean Peninsula in 2014.

The Russian president set the stage for such moves even before Russia’s Feb. 24 invasion of Ukraine, writing an essay last summer claiming that Russians and Ukrainians are one people and attempting to diminish the legitimacy of Ukraine as an independent nation. Reports have surfaced of Russian authorities confiscating Ukrainian passports from some citizens.

The passport announcement came hours after Russian shelling of Ukraine’s second-largest city today killed at least six people and injured 31, prosecutors and local officials said. Russian troops launched three missile strikes on Kharkiv, Ukraine’s second-largest city, in an attack one official described as “absolute terrorism.”

Russia’s Defense Ministry said the attacks struck at the points of deployment for Ukraine’s “nationalist battalions.” Kharkiv regional Gov. Oleh Syniehubov said on Telegram that the shelling came from multiple rocket launchers, and those wounded and hospitalized included children aged 4 and 16.

“Only civilian structures — a shopping center and houses of peaceful Kharkiv residents — came under the fire of the Russians. Several shells hit the yards of private houses. Garages and cars were also destroyed. Several fires broke out,” Syniehubov wrote.

Earlier, he said one missile destroyed a school, another hit a residential building, while the third landed near warehouse facilities.

“All (three were launched) exclusively on civilian objects. This is absolute terrorism!” Syniehubov said.

Kharkiv resident Alexander Peresolin said the attacks came without warning, with a blast so fierce he lost consciousness. Neighbors carried him to the basement, where he regained consciousness.

“I was sitting and talking to my wife,” he said. “I didn’t understand what happened.”

The strikes came two days after a Russian rocket attack struck apartment buildings in eastern Ukraine. The death toll in that attack on the town of Chasiv Yar rose to 31 today. Nine people have been rescued from the rubble but more are still believed trapped, emergency officials said.

The attack late Saturday destroyed three buildings in a residential quarter used mostly by people who work in factories. Russia’s Defense Ministry insisted today that the Chasiv Yar target “was a Ukrainian territorial defense brigade, and that “more than 300 nationalists” were killed. The town is also the hometown of Ukraine’s president.

Russian attacks continued in eastern Ukraine, with Luhansk regional Gov. Serhiy Haidai saying today that Russian forces carried out five missile strikes and four rounds of shelling, hitting settlements on the border with the Donetsk region.

The Luhansk and Donetsk regions make up Ukraine’s eastern industrial heartland known as the Donbas, where separatist rebels have fought Ukrainian forces since 2014. Earlier this month, Russia captured the last major stronghold of Ukrainian resistance in Luhansk, the city of Lysychansk.

Ukrainian forces continued attacks on what they said are Russian ammunition depots, in a prelude to a possible counteroffensive to retake Russian-occupied territory.

Ukrainian officials said on social media late today that an ammunition depot in Novy Kakhovka, in the mostly Russia-occupied Kherson region, was destroyed.

Russia’s Tass news agency offered a different account, saying that the target was a mineral fertilizer storage facility that exploded and that a market, hospital and houses were damaged. Some of the ingredients in fertilizer can be used as ammunition.

Tass said there were casualties, without providing an estimate, and claimed the weapon used in the strike was fired from a U.S-supplied multiple-launch High Mobility Artillery Rocket Systems, or HIMARS. Ukrainian officials didn’t comment on the type of weapon used.

Also today:

— The main Russian natural gas pipeline to Germany began a 10-day closure for maintenance, heightening European fears that Moscow may not turn the flow back on after its completion. The Nord Stream 1 pipeline runs under the Baltic Sea from Russia to Germany and is the latter’s main source of Russian gas. Gas is usually sent onward to other countries as well. It is scheduled to be out of action until July 21. German officials are suspicious about Russia’s intentions, particularly after Russia’s giant energy firm Gazprom last month reduced the gas flow through Nord Stream 1 by 60%. Ukrainian President Volodymyr Zelenskyy said in a video address today, “There can be no doubt that Russia will try not just to limit as much as possible, but to completely shut down the supply of gas to Europe at the most acute moment. This is what we need to prepare for now, this is what is being provoked now.”

— Western nations pledged more support and military supplies to Ukraine. In Kyiv, Dutch Prime Minister Mark Rutte told Zelenskyy that his country would supply self-propelled howitzers and artillery shellsn. Rutte also pledged financial support for Ukrainian teachers, doctors and retirees. Zelenskyy said he spoke with Rutte about the Netherlands’ potential role in the reconstruction of Ukraine.

— The White House today said it believes Russia is turning to Iran to provide hundreds of unmanned aerial vehicles, including weapons-capable drones, for use in its invasion of Ukraine. U.S. National Security Adviser Jake Sullivan said it was unclear whether Iran had already provided the systems, but said the U.S. had “information” indicating Iran was preparing to train Russian forces to use them as soon as this month.

Jovana Gec in Belgrade, Serbia, contributed to this report.