(Reuters) - Ukraine's commander in chief and its defence minister discussed military aid and the frontline situation with senior U.S. officials on Monday, Commander Oleksander Syrskyi said.

Syrskyi, writing on the Telegram messaging app, said he and Defence Minister Rustem Umerov had a discussion with U.S. national security advisor Jake Sullivan, Defense Secretary Lloyd Austin and Charles Brown, chairman of the Joint Chiefs of Staff.

"We spoke about the situation at the front, as well the assistance that Ukraine needs on the battlefield," Syrskyi wrote.

Equipment and munitions from a $61 billion aid package approved last month after months of delays owing to congressional wrangling has begun arriving in Ukraine.

(Reporting by Ron Popeski; Editing by Chris Reese)