Johnson’s intervention follows President Zelensky’s visit with a number of prominent Democrats to an armaments manufacturing in Scranton, Pennsylvania, the home town of President Joe Biden in a crucial swing state.
The leading Republican charged that the visit amounted to “election interference” and was “designed to help Democrats” in a letter made public.
Zelensky will meet with President Joe Biden on Thursday to offer a “plan for victory” in his nation’s fight with Russia, but the controversy has the potential to overshadow the meeting.
Zelensky has increased his attempts to convince the US and other countries since his arrival in the US on Sunday.
As his presidency comes to a close, Biden said on Thursday that the US will send $7.9 billion (£5.9 billion) in military aid to Ukraine.
Long-range weapons and more Patriot air defense missiles are included in the assistance, which is a portion of a $61 billion plan approved by Congress in April.
In order to expedite the delivery of the arms, the weapons package will be authorized through presidential drawdown authority and will utilize already-existing Pentagon stocks.
Before giving down and allowing the legislation to pass in April, congressional Republicans obstructed the Biden administration’s $61 billion military plan for several months earlier this year.