KIEV (Reuters) - Ukraine's military said on Friday more than 20 Russian tanks, 10 missile systems and bus-loads of fighters had crossed Ukraine's border and headed towards Novoazovsk, a rebel-held town east of the strategic southeastern port city of Mariupol.

"In recent days, despite the Minsk (ceasefire) agreement, military equipment and ammunition has been tracked crossing from Russia into Ukraine," military spokesman Andriy Lysenko said in a televised briefing.

"More than 20 (tanks, 10 self-propelled artillery systems and 15 trucks have entered in the direction of Novoazovsk," he said, adding that buses filled with fighters from Russia had also been spotted crossing the border in the area.

(Reporting by Natalia Zinets; Writing by Alessandra Prentice, editing by Elizabeth Piper)