US Defense Secretary Lloyd Austin believes a Russian breakthrough in the eastern Ukrainian region of Kharkiv is unlikely.
"A couple of weeks ago, there was concern that we would see a significant breakthrough on the part of the Russians," Austin said on the sidelines of a NATO defence ministers' meeting in Brussels.
"I don't think we'll see that going forward."
The Ukrainians had done a lot to strengthen their defence positions in the eastern border region and were making good use of the weapons and ammunition provided to them.
"And more of that will continue to flow in, the defence minister of Ukraine's strongest supporter said. However he acknowledged "it will take some time" for the additional support to play out on the battlefield.
However Austin, when asked, said he had nothing to say about whether the US would supply Ukraine with another Patriot air defence system, as reported by several US media.
Russia launched an offensive on the Kharkiv region in mid-May, occupying several Ukrainian border villages. Although there has been no major breakthrough so far, the regional capital, also called Kharkiv, continues to be subjected to massive shelling.
Several Western allies - including the United States and Germany - recently allowed Ukraine to attack targets on the Russian side of the border with weapons supplied by them to defend Kharkiv.
"I don't have any announcements on Patriot batteries today," Austin said.
