By Tim Lister and Daria Tarasova-Markina, CNN

(CNN) — Russia is likely to mobilize another 300,000 troops later this year, according to Ukrainian President Volodymyr Zelensky, as it tries to complete the capture of a long-coveted region of east Ukraine.

In wide-ranging remarks released Sunday, Zelensky said he expected that the Russians would end the year occupying the same amount of Ukrainian territory as at the beginning of the year, despite enormous losses of manpower.

“Russia has lost 267,000 personnel since the start of the year, including around 155,000 killed to date,” Zelensky claimed.

The figure is impossible to confirm but in line with estimates by Western officials.

Russian parliamentary elections take place next month, and there has been speculation about a fresh mobilization despite a 2022 draft triggering protests and an exodus of young men.

“We are confident that following the elections, they will carry out a mobilization. We believe this will not take place in the major cities,” Zelensky said.

Zelensky said he believed Putin would “deploy the 300,000 newly mobilized troops depending on the situation in the east of our country,” and had told his generals to complete the occupation of Donetsk by the end of the year.

“They’ll lose all 300,000 of these newly mobilized Russians there; we’ll wipe them out,” Zelensky asserted.

Ukrainian units are defending some 20% of Donetsk, including a belt of strategic industrial towns such as Slaviansk and Kramatorsk.

Zelensky said it was impossible for the Russians to complete the capture of Donetsk region. He suggested the Russians might also attempt an incursion into the northern Ukrainian regions of Kharkiv and Sumy.

“They do not yet have troops in the Bryansk region (which borders northern Ukraine), but we can see military equipment along the borders with the Russian Federation.”

Musk, Kushner, and air defenses

On air defenses, Zelensky contrasted the number of Patriot missiles supplied in 2023 – which was 675 – with the forecast number of 264 this year. Ballistic missile attacks have increased civilian casualties and infrastructure damage across Ukraine – and Patriots are the only means of shooting them down.

“As you can see, there is, unfortunately, a downward trend, and this depends primarily on the American side,” he said.

Last month, US President Donald Trump suggested Ukraine would be permitted to build Patriot missiles on license, but later backed away from the idea.

If the US would supply up to 10% of its Patriot missile stocks to Ukraine, Kyiv would pay for them, Zelensky said. Such a commitment “could make a huge difference, both in terms of saving lives and diplomatically as well.”

Ukraine faces the same problem in acquiring Aster air defense missiles from Europe, according to Zelensky, despite a recent pledge by French president Emmanuel Macron.

“There aren’t enough ‘Aster’ missiles, even though they are being produced,” he said – though added a licensing agreement would accelerate supplies.

Kyiv’s long-range missile program will get a boost Monday when new British Prime Minister Andy Burnham makes his first official visit to Ukraine.

London has agreed to allow defense firm MBDA to release classified information on UK components to help Ukraine build its own long-range SCALP missiles, the French-produced version of the UK’s Storm Shadow.

In the meantime, Ukraine is hunting the sites in Russia from where ballistic missiles are launched, according to Zelensky.

Russia’s military industries may be capable of building about 1,300 ballistic missiles a year, Zelensky said. “There are specific objectives regarding strikes on military targets and other anti-ballistic sanctions,” he said.

Ukraine has developed an arsenal of long-range drones and its own cruise missiles which are being used against a widening array of targets inside Russia.

He also spoke about Kyiv’s efforts to get permission to use Starlink satellite imagery of Russian territory.

Elon Musk, who owns Starlink, said he “believed that this could lead to a major escalation against the Russian Federation on Ukraine’s part,” according to Zelensky.

“He said he was in favor of ending the war, not prolonging it” – and discussions with Washington were continuing.

As for negotiations, Zelensky suggested that the window of opportunity for ending the war stretched through the end of next summer, when the US presidential election campaign would begin.

US envoys Steve Witkoff and Jared Kushner were “finding it very difficult to find a format whereby the Russians would agree to end this war without Ukraine having to withdraw from Donbas or accept other unacceptable solutions.”

“Jared, Steve and I agreed to summarize all these discussions on a single page – setting out the realistic options for ending the war. This is what the Americans want to discuss with us and with the Russians.”