Top US officials visit Kyiv as Mariupol 'on the brink'

The United States' top diplomat and defence chief were in Ukraine's capital Sunday, Kyiv said, making the first high-level visit by US officials since Russia invaded two months ago as hundreds remain trapped in the besieged city of Mariupol.

The trip by Secretary of State Antony Blinken and Defence Secretary Lloyd Austin comes as the war enters its third month, with thousands dead and millions displaced.

Presidential adviser Oleksiy Arestovych said Ukrainian leader Volodymyr Zelensky met the US officials Sunday, as Mariupol's defences were "already on the brink of collapse" and Ukraine was in dire need of offensive weapons.

"As long as there are no 'offensives', there will be a new Bucha every day," he said in an interview on a Russian former lawyer's popular YouTube channel, referring to the town where UN officials said they had documented the unlawful killings of around 50 civilians.

"Maybe they can help," Arestovych added of the US envoys.

"They wouldn't come here, if they weren't ready to give (weapons)." While the visit remained unconfirmed by Washington and details were kept under wraps, Zelensky tweeted later Sunday that the "Ukraine-US friendship and partnership are stronger than ever".

The United States has been a leading donor of finance and weaponry to Ukraine and a key sponsor of sanctions targeting Russia, but had not yet sent any top officials to Kyiv, while several European leaders had travelled there to underscore their support.

United States diplomats will begin a gradual return to Ukraine this week, Washington's secretary of state and defence chief said Monday, as they announced $700 million in military aid during their first war-time visit to Kyiv.

The trip by Secretary of State Antony Blinken and Defence Secretary Lloyd Austin -- which the United States confirmed only after the two had left Ukrainian territory -- came as the invasion entered its third month, with thousands dead and millions displaced.

Presidential adviser Oleksiy Arestovych said Ukrainian leader Volodymyr Zelensky met the US officials Sunday, as the port city of Mariupol's defences were "on the brink of collapse" and Kyiv was in dire need of offensive weapons.

Washington ordered the withdrawal of its diplomats in the weeks prior to Russia's February invasion of Ukraine, but has been a leading donor of financial aid and weaponry to the country, and a key sponsor of sanctions targeting Moscow.