US National Security Advisor Jake Sullivan said on Friday that Washington is worried about the personal safety of Ukrainian President Vladimir Zelensky. The US is assisting Zelensky with his security, Sullivan added.

“President Zelensky’s personal safety is something that concerns us,” Sullivan told the Aspen Security Forum in Colorado. “This is a leader in wartime, dealing with an enemy in Russia that is ruthless, brutal and capable of just about anything.”

“President Zelensky takes the precautions you would expect to protect himself,”Sullivan continued, adding that the US is helping to “facilitate” the Ukrainian leader’s security, without elaborating.

The US offered to evacuate Zelensky from Kiev when Russia launched its military operation in Ukraine in February. Zelensky did not take up the offer. This week, Ukraine’s parliament approved the firing of Ivan Bakanov, the top official at the state security service (the SBU). Zelensky also removed the heads of SBU departments in five of the country’s regions. Bakanov was a close associate of Zelensky, and the pair had worked together since the latter’s days in comedy.

Ukraine’s president has claimed on several occasions that assassins have threatened his life, and his officials said numerous times that Russia intends to have the president killed. Moscow denies these allegations, with Kremlin spokesman Dmitry Peskov stating in April that Zelensky “is the president of Ukraine,” and Russia wants him to sit down and agree to its terms for peace.

Asked whether he worries about declining public support for Ukraine at home, Sullivan said that he worries “about literally everything,”except the arms pipeline to Kiev.

The $40 billion military and economic aid bill signed by US President Joe Biden in May allocates “enough resources to keep weapons flowing for some time,” Sullivan stated, adding that even though public support for Ukraine may be dipping, there is a “reservoir” of “deep and sustainable support” in the White House and Congress.

Should the tens of billions of dollars run out, Sullivan said that “there will be bipartisan support in the Congress to re-up those resources should it become necessary.”

As Sullivan spoke in Aspen, National Security Council spokesman John Kirby announced that the Biden administration would send a fresh tranche of weapons worth $270 million to Ukraine, including four HIMARS rocket artillery systems. The US has given Ukraine a dozen of these truck-mounted weapons platforms already, although Russia claims to have destroyed four during the last three weeks.