KIEV (NYTIMES) - US Defence Secretary James Mattis vowed to help Ukraine stand up to Russian violations of its sovereignty and signalled that the Trump administration was considering providing defensive weapons to the Ukrainian military.

Former president Barack Obama had resisted such a step, fearing it would be seen as a provocation by Russia. In the first visit to Ukraine by a US defence secretary in nearly a decade, Mr Mattis seemed to be anticipating that argument.

"Defensive weapons are not provocative unless you are an aggressor, and clearly Ukraine is not an aggressor since it is their territory where the fighting is happening," Mr Mattis said at a joint news conference with Ukraine's President Petro O. Poroshenko on Thursday (Aug 24).

State and defence department officials have recommended that the United States provide Javelin anti-tank missiles and other defensive weapons to Ukraine to strengthen its forces and raise the potential cost to the Kremlin of a Russian attack.

But President Donald Trump has yet to take up the matter.

Mr Mattis declined to disclose what he planned to recommend to Mr Trump. But his comments suggested that he was sympathetic to supplying defensive weapons - long a topic of enormous interest in Ukraine.

"On the defensive lethal weapons, we are actively reviewing it," he said. "I will go back now having seen the current situation and be able to inform the Secretary of State and the President in very specific terms what I recommend for the direction ahead."

While the Obama administration had rejected providing the Javelin anti-tank system to Ukraine, the context has shifted in recent years.

The failure of the Minsk peace agreement, which was negotiated by Russia, Ukraine and European nations in 2015, and Russia's active military posture in the region, have combined to bring the issue to the fore.

Mr Poroshenko sought to buttress Ukraine's case by saying that it had responsibly used the non-lethal systems it had already received from the US, and asserting that the anti-tank weapon would be used to deter further Russian aggression.

But German Chancellor Angela Merkel strongly opposed the provision of such weapons when it was considered by Mr Obama in 2015, saying that they would merely inflame the military situation.