At least three more Ukrainian soldiers were killed, and 13 others were injured over the last 24 hours, as government forces clashed with pro-Russian separatist rebels in Ukraine's eastern region, sources told Al Jazeera.
The army offensive continued on Saturday around Donetsk and Luhansk, even as Ukraine and Russia reached a tentative agreement to bring humanitarian aid to thousands of Ukrainian civilians caught in the fighting.
In Donetsk, government forces "liberated" the town of Zhdanovka from rebel control, according to the office of Ukrainian President Petro Poroshenko.
Andrei Lysenko, a government spokesman, said that in the Ukrainian city of Debaltsevo at least 13 men aged 20 to 45 were also arrested for alleged "terrorist activities".
He also said that because of the government advance rebels had been forced to retreat.
In the city of Luhansk, Lysenko said that 300 separatists had already removed the flag of the self-proclaimed Luhansk People's Republic.
In Yenkievo and Horlivka, suspected Chechen fighters were also reportedly seen abandoning their posts.
Separatist fighters were also reported to be trying to leave Donetsk. Many of the pro-Russian rebels and residents have been accused of using fake documents to allow them to leave as refugees.
In a separate developement, Al Jazeera has learned that the Red Cross aid agency has been designated by the Ukrainian and Russia governments to facilitate the transport of humanitarian aid to civilians.
Moscow demanded that Kiev allow its mammoth aid convoy to cross the volatile border but Ukraine suspected the convoy was being used as a ploy to invade eastern Ukraine.
Some 280 trucks packed with what Russia says is humanitarian aid waited for a third day some 30 km from a rebel-held border post.
The West and Kiev fear the convoy could be a "Trojan horse" to bolster the flagging pro-Kremlin rebellion in eastern Ukraine or provide Moscow with an excuse to send in the 20,000 troops that NATO says it has amassed on the border.
Four months of fighting has killed over 2,000 people and left the region facing a humanitarian disaster.
The latest spike in tensions came after Ukrainian President Petro Poroshenko claimed his troops had blown up part of a small Russian military convoy that British media spotted breaching the porous frontier on Thursday.
Russia dismissed the claims as "fantasies", its latest denial of persistent allegations from the West that it is arming the rebels.