More than 80 unmarked military vehicles were seen moving through parts of eastern Ukraine held by pro-Russian separatists on November 8, the Associated Press (AP) news agency reports.
AP reporters took photos and video of three columns of armed vehicles and other military hardware: one near the city of Donetsk and two near Snizhne.
Most of the vehicles were transport trucks but there was at least one armored personnel carrier.
AP said several of the trucks were carrying troops.
Ukrainian military officials reported this week that separatist forces received large amounts of weaponry and troops from Russia, including 32 tanks and howitzer artillery pieces crossing into Ukraine from Russia on November 6.
Russia has denied providing any weapons or troops to the separatists.
Ukraine said on November 8 that three soldiers were killed and 15 wounded in fighting in the last 24 hours.