Ukraine is "still in a state of war" with neighbouring Russia despite a cease-fire between Kiev's forces and Moscow-backed rebels in the east, the country's prime minister said Saturday shortly after a second convoy of Russian trucks rolled into Ukraine.

Speaking at a conference with politicians and business leaders in Kyiv, Arseniy Yatsenyuk said Russian President Vladimir Putin's "goal is to take the entire Ukraine."

"He cannot cope with the idea that Ukraine would be a part of a big EU family. He wants to restore the Soviet Union," Yatsenyuk said.

He didn't mention the second convoy of Russian trucks that entered rebel-held territory in eastern Ukraine earlier Saturday, reportedly filled with almost 2,000 tons of humanitarian aid.

The last truck crossed onto Ukrainian soil early Saturday from the Russian border town Donetsk, some 200 kilometres east of the Ukrainian city with the same name, Rayan Farukshin, a spokesman for Russia's customs agency, told the Associated Press by phone. He could not confirm the number of trucks, but news agency ITAR TASS reported that about 250 trucks were heading toward the city Luhansk.

The Russian emergency ministry, which coordinated previous humanitarian aid deliveries to Ukraine, could not be reached for comment about the convoy.

Aid convoy crossed 'illegally'

Col. Andriy Lysenko, a spokesman for the Ukrainian National Security and Defense Council, told journalists Saturday that the convoy had crossed "illegally" onto Ukrainian territory.

"Ukraine border guards and customs were not allowed to examine the cargo and vehicles," he said. "Representatives of the Red Cross don't accompany the cargo, nobody knows what's inside."

Ukraine

Trucks with Russian flags, reportedly carrying 2,000 tons of humanitarian aid, stationed on the Russian side of the Ukrainian-Russian border on Friday, a day before they entered rebel-held territory in eastern Ukraine. (The Associated Press)

Lysenko's relatively mild comments on the second convoy and the silence of more senior Ukrainian officials shows how dramatically the mood has shifted in the Kyiv government since August. President Petro Poroshenko has been at pains to prove that last week's ceasefire deal has yielded improvements on the ground in east Ukraine. On Friday, he lauded the deal, which has been riddled by violations since it was imposed last week, as a "fragile but efficient peace process."

In August, Ukrainian officials said that a first convoy of humanitarian aid from Russia would be seen as an invasion of the country and loudly protested any attempts by Russia to unilaterally bring in the aid. Eventually, Russia sent its trucks across the border and into rebel-held territory without the oversight of the International Red Cross, contrary to an agreement signed between Ukraine and Russia.

A representative of the ICRC's Moscow office said they had not been informed about the current convoy, either.

"We were not officially notified of an agreement between Moscow and Kyiv to ship the cargo," Galina Balzamova said Saturday.

Fighting near Donetsk airport

Lysenko said that six Ukrainian servicemen had died since the truce. He also confirmed that 12 rebel fighters had been killed by Ukrainian forces near Sea of Azov city of Mariupol, where he said they were doing reconnaissance work — the first such admission that they have inflicted casualties on the rebel side since the ceasefire began.

In a statement posted online early Saturday, the Donetsk city council said that there had been fighting near the airport throughout the night. Two shells had hit residential buildings in the area, but no casualties were reported.

Continuous rocket fire could be heard overnight in downtown Donetsk, and a column of three GRAD rocket launchers — all its rockets still in place — was seen moving freely through the rebel-held city on Saturday morning.