U.S. Secretary of State Antony Blinken said this during an interview with Sky News on Tuesday, Ukrinform reports.
Blinken said the U.S. had made sure Ukraine had "what it needed, when it needed it, to be effective in repelling the Russian aggression" since Moscow's launch of its February 2022 invasion.
He added that Washington had also had to consider other factors, such as whether Ukraine's forces can use the "sophisticated systems" Western allies are providing and whether they can maintain them.
"All of those things have to go into these decisions. But what I can tell you is, we've adapted and adjusted every step along the way, and we'll continue - so not ruling out at this stage," Blinken noted in the context of a possible decision to allow Ukraine to launch deep strikes into Russian territory.
"We don't. We never rule out. But when we rule in, we want to make sure it's done in such a way that it can advance what the Ukrainians are trying to achieve," Blinken said.
