KYIV, Ukraine (AP) — Russian President Vladimir Putin signed the final papers Wednesday to annex four regions of Ukraine while his military struggled to control the new territory that was added in violation of international laws.

The documents finalizing the annexation were published on a Russian government website. In a defiant move, the Kremlin held the door open for further land grabs in Ukraine.

Speaking in a conference call with reporters, Kremlin spokesman Dmitry Peskov said that “certain territories will be reclaimed, and we will keep consulting residents who would be eager to embrace Russia.”

Peskov did not specify which additional Ukrainian territories Moscow is eyeing, and he wouldn’t say if the Kremlin planned to organize more such “referendums.”

Putin last week signed treaties that purported to absorb Ukraine’s Donetsk, Luhansk, Kherson and Zaporizhzhia regions into Russia. The move followed Kremlin-orchestrated “referendums” in Ukraine that the Ukrainian government and the West have dismissed as illegitimate.

The Russian president defended the validity of the vote, saying it’s “more than convincing” and “absolutely transparent and not subject to any doubt.”

“This is objective data on people’s mood,” Putin said Wednesday at an event dedicated to teachers, adding that he was pleasantly “surprised” by the results.

On the ground, Russia faced mounting setbacks, with Ukrainian forces retaking more and more land in the eastern and southern regions that Moscow now insists are its own.

The precise borders of the areas Moscow is claiming remain unclear, but Putin has vowed to defend Russia’s territory — including the annexed regions — with any means at his military’s disposal, including nuclear weapons.

Shortly after Putin signed the annexation legislation approved by Russia’s parliament, the head of Ukrainian President Volodymyr Zelenskyy’s office, Andriy Yermak, wrote on his Telegram channel that “the worthless decisions of the terrorist country are not worth the paper they are signed on.”

“A collective insane asylum can continue to live in a fictional world,” Yermak added.

Zelenskyy responded to the annexation by announcing Ukraine’s fast-track application to join NATO. In a decree released Tuesday, he also ruled out negotiations with Russia, declaring that Putin’s actions made talking to the Russian leader impossible.

On the battlefield, Russia and Ukraine gave conflicting assessments of a Ukrainian counter-offensive in the Russian-occupied Kherson region. A Moscow-installed regional official insisted that Ukrainian advances had been halted.

“As of this morning … there are no movements” by Kyiv’s forces, Kirill Stremousov said Wednesday in comments to state-run Russian news agency RIA Novost. He vowed the Ukrainian fighters would not enter the city of Kherson.

However, the Ukrainian military said the Ukrainian flag had been raised above seven Kherson region villages previously occupied by the Russians. The closest of the liberated villages to the city of Kherson is Davydiv Brid, some 100 kilometers (60 miles) away.

The deputy head of the Ukrainian regional government, Yurii Sobolevskyi, said military hospitals were full of wounded Russian soldiers and that Russian military medics lacked supplies. Once they are stabilized, Russian soldiers were getting sent to Crimea, which Russia annexed from Ukraine in 2014.

“Not everyone arrives,” Sobolevskyi wrote.

In the Moscow-annexed Donetsk region, where Ukrainian forces still control some areas, Russian forces shelled eight towns and villages, the Ukrainian presidential office said.

After reclaiming the Donetsk city of Sviatohirsk, Ukrainian forces located a burial ground for civilians and found the bodies of four people, according to Gov. Pavlo Kyrylenko.

In central Ukraine, multiple explosions rocked Bila Tserkva, a city about 80 kilometers (50 miles) south of the capital, Kyiv. The blasts set off fires at what were described as infrastructure facilities, regional leader Oleksiy Kuleba said on Telegram.

Early indications were that the city was attacked with so-called kamikaze or suicide drones, he said.

Russia has increasingly employed suicide drones in recent weeks, posing a new challenge to Ukrainian defenses. The unmanned vehicles can stay aloft for long periods of time before diving into targets and detonating their payloads at the last moment.

Many of the earlier attacks with the Iranian-made drones happened in the south of Ukraine and not near the capital, which hasn’t been targeted for weeks.

In a later post, Kuleba said a total of six Shahed-136 drones struck Bila Tserkva, one of the largest cities in the capital region after Kyiv. One person was wounded.

Elsewhere in Ukraine, at least five civilians were killed and eight others were been wounded by Russian shelling in 24 hours, according to Zelenskyy’s office.