Ukraine's military and pro-Russian separatists have reported new casualties amid growing fears of an escalation of the conflict that has shattered ties between Moscow and the West, while Russia firmly denies it has any soldiers in eastern Ukraine.
The Ukrainian military said on November 13 that four of its soldiers had been killed and 18 wounded in fighting with the rebels over the previous 24 hours.
It said the fighting was concentrated in the area of the international airport outside Donetsk, one of two rebel-held provincial capitals in eastern Ukraine, and the village of Debaltseve near the border with the Luhansk region.
Separatist authorities in the self-proclaimed "Donetsk People's Republic" said three people were injured by artillery shelling in Donetsk overnight and reported an ongoing bombardment of rebel positions near Debaltseve.
In Kyiv, military spokesman Andriy Lysenko said shelling by separatists in both the Luhansk and Donetsk regions had intensified, but that Ukrainian forces have no intention of renouncing a September 5 cease-fire.
The truce has been violated daily, with each side blaming the other.
Lysenko said a buildup of forces in the areas the separatists control signaled they were planning a new offensive in a conflict that has killed more than 4,000 people since April and driven Russia's ties with the West to post-Cold War lows.
Ukrainian President Petro Poroshenko, meanwhile, told journalists in Kyiv on November 13 that the border between Russia and Ukraine continues to be "repeatedly crossed by Russian regular forces."
'A Return To Full-Scale Fighting'?
On November 12, the UN Security Council -- in which Russia and the United States have the power to block resolutions -- met in an emergency session on Ukraine's crisis for the 26th time, again without taking action.
UN Assistant Secretary-General for Political Affairs Jens Anders Toyberg-Frandzen told the council that the UN was "deeply concerned over the possibility of a return to full-scale fighting" in eastern Ukraine.
He said the country could also face a months-long simmering conflict that would be catastrophic, or the situation in eastern Ukraine could become a "frozen" conflict that lingers for years or even decades.
Kyiv and Western governments are concerned that Russian President Vladimir Putin may want the separatists to seize more territory in Ukraine or solidify control over the areas where the rebels elected leaders and legislatures in November 2 elections dismissed by the United States and European Union as illegitimate violations of the September 5 truce agreement, which also called for other measures to end the conflict.
The meeting came hours after NATO's top commander said "multiple columns" of Russian tanks, artillery, and antiaircraft units had crossed from Russia into separatist-controlled territory over the previous two days.
Russian issued its clearest denial yet of a military presence in eastern Ukraine, saying that there are no Russian soldiers there.
"I tell you completely candidly and officially that there have not been and are no military movements across the border, let alone a presence of our military personnel on the territory of Ukraine," Foreign Ministry spokesman Aleksandr Lukashevich said.
He said Russia is doing everything it can to prevent an escalation of the conflict and accused Kyiv of violating the September 5 peace agreement.
Luakshevich said Russia was talking to the Organization for Security and Cooperation in Europe (OSCE) observer mission "about what they said in their report," referring to the monitors' sightings of unmarked military convoys in rebel-held territory in eastern Ukraine in recent days.
Lukashevich added that the collapse of the cease-fire "must not be allowed.... It would be catastrophic for the situation in Ukraine."
Kyiv and Western governments have dismissed Moscow's denials, pointing to evidence including sightings of convoys and numerous funerals of Russian soldiers that have been held in Russia in recent months.
Lysenko, the Ukrainian spokesman, said there has been no let-up in the flow of military equipment to the rebels from Russia.
A top official from the OSCE said the observer mission in eastern Ukraine faces "unacceptable restrictions" on its mandate to monitor the border with Russia.
Ilkka Kanerva, the president of the OSCE's Parliamentary Assembly, told the OSCE Permanent Council in Vienna on November 13 that monitors are limited to reporting "only what it sees pass through the official crossing along the tiniest strip of the border."
Kanerva asked, "If we are not permitted to do it right, the question is -- is it worth to do it at all?"
With reporting by dpa and Interfax