Update at 5:00 p.m. ET
After being halted at the border for more than a week, a Russian aid convoy is rumbling into eastern Ukraine without permission, prompting Kiev to label the move a "direct invasion" of sovereign territory.
Karoun Demirjian, reporting for NPR from Moscow, says 150 Russian trucks arrived in the rebel-held city of Luhansk on Friday.
Earlier, Ukraine refused to allow the trucks across the border because it feared they might be carrying weapons and other militarily useful supplies for Moscow-backed rebels, or, worse, be a prelude to a full-scale Russian invasion.
"That's something that Russia has denied, but both Western officials and officials in Kiev dispute that," NPR's Soraya Sarhaddi Nelson reports from eastern Ukraine. "They believe there is some indication that that is going on."
However, officials from the International Committee of the Red Cross inspected at least some of the vehicles and affirmed that they were carrying only humanitarian aid, she says.
"What the Red Cross has said is that there are humanitarian goods in the trucks that they've looked at — generators, blankets, water, food stuffs — and these are things that are apparently in the trucks that are supposedly moving in the direction of Luhansk," Soraya says.
Speaking at a Pentagon briefing this afternoon, Rear Adm. John Kirby had strong words over the movement of the convoy, saying Moscow had violated Ukraine's "sovereignty and territorial integrity.
"Russian must remove its vehicles and its personnel from Ukraine immediately," he told reporters. "Failure to do so will result in additional costs and isolation."
Kirby said there continued to be concern about "very ready, very capable, very mobile" Russian troops on the border. He put the number at "well north of 10,000.
"We are seeing a lot of hardware going across that border on a daily basis," he said, referring to weapons and military supplies being sent to separatists.
United Nations General Secretary Ban Ki-moon expressed "deep concern" over the Russian action. "While recognising the deteriorating humanitarian situation, any unilateral action has the potential of exacerbating an already dangerous situation in eastern Ukraine," he said.
Following closed consultations on Ukraine by the U.N. Security Council, of which Russia is a veto-wielding member, British Ambassador Mark Lyall Grants said many expressed concern over Moscow's unilateral and illegal act. He said Russia defended its action on the basis of humanitarian need.
"Kiev, for its part, said Ukrainian forces would not attack the convoy and had allowed it to pass to avoid 'provocations.'
" 'Ukraine will liaise with the International Committee of the Red Cross so that we, Ukraine, are not involved in provocations (accusations) that we have been holding up or using force against the vehicles of so-called aid,' he told journalists."
By way of background, The Associated Press writes:
"In the past few days, Ukraine says its troops have recaptured significant parts of Luhansk, the second-largest rebel-held city, and suspicions are running high that Moscow's humanitarian operation may instead be aimed at halting Kiev's military momentum. Fierce fighting has been reported both around Luhansk and the largest rebel-held city, Donetsk, with dozens of casualties.
"The International Committee of the Red Cross, which had planned to escort the Russian aid convoy to assuage fears that it was being used as a cover for a Russian invasion, said it had not received enough security guarantees to do so."