By Rachael Leighton, BBC World ServiceThe Kremlin-backed separatists in Ukraine have said they will begin “armed struggle” in the east of the country on Wednesday after Russia accused them of preparing a “provocation” that could trigger a “civil war” in Crimea.
In a statement issued by the Russian Defence Ministry, it said Ukrainian forces had “infiltrated” a Russian-speaking village near its border with Crimea.
A ceasefire was in place for 10 days, but the separatists are “working hard to prevent it from lasting longer”, it added.
In its statement, the Russian Foreign Ministry also accused Ukraine of sending “terrorists” to attack Russian-speakers in Crimea, which is annexed by Moscow from Ukraine.
The separatist government said in a statement it had ordered its forces to “take the necessary steps” in order to protect themselves.
“We have been warned by the authorities that there is a threat of a provocation by terrorists against our people, the residents of Crimea,” it said.
A Russian Defence ministry spokesman said it was “absolutely clear” the threat posed by Ukrainian forces was real.
The Ukrainian defence ministry later issued a statement saying Russian military forces were “attacked by Russian military personnel” in an area near its borders with Crimea and in the Donbas region of the south.
“The Ukrainian side has the right to defend itself against such provocation,” the ministry said.
“If Russian servicemen attack the Russian-language village near our borders, we will respond immediately,” the statement said.
Russia has been accused of deploying military assets in the region.
A spokesman for the Russian Federation’s foreign ministry said: “Russia will not allow a provocations in the Ukraine region and will not accept any provocation.
The country will not hesitate to use all the tools at its disposal to protect the people of Crimea and the territorial integrity of Ukraine.”
The Russian Foreign Minister, Sergei Lavrov, was speaking at a news conference after meeting with the heads of the Russian military, civil defence and military industrial complexes.
Lavrov also said the separatists had sent a letter to Ukrainian President Petro Poroshenko, accusing him of violating a peace deal reached in Minsk, Belarus, in February.
“Our military and our civil defence forces have been mobilized in Crimea,” he said.
Ukraine’s military and civil defence agencies said they had received a call from Russian soldiers, saying the attack was a provocation.
“It is a provocation that threatens the lives of Ukrainian citizens, the security of Ukrainian territory, and the sovereignty of Ukraine,” a Ukrainian military official said.
Poroshenko said the separatist attack had “absolutely nothing to do with the peace agreement”.
He said his government was taking all necessary measures to defend Ukraine.
“I am fully aware of the serious threats posed by the actions of our armed forces and of our security services.
All the measures we take will have to be proportional and proportionate to the threat,” Poroshenko said.
The Kremlin has repeatedly accused Ukraine’s armed forces of taking part in an “anti-Russian” campaign.
Russia’s foreign minister, Sergei Ivanov, said the attack on the village had nothing to with the agreement reached in February to end the war in eastern Ukraine.
He also said there was no evidence that the Ukrainian military had been involved in the operation.
He said the military was “not targeting anyone, no, not a single Ukrainian soldier, and not a military base” – a reference to the military base near the Ukrainian city of Krasnodar where Russian troops have been stationed for years.
Ukrainian soldiers stand guard on a road near a Russian military base, near Krasnyi Luch, east of Kiev, on January 24, 2017.
Ukriya Kravchuk/AP”There’s no evidence of any Russian troops in the area,” he told reporters in Kyiv.
“What we have here is an act of provocation.
They are using military force to protect their own territory, which means the territory of our neighbours.””
They have no right to carry out this provocation,” Ivanov said.
“The people of Ukraine are our neighbours, and we will defend them.”
In the past, Russia has said it had used armed forces to quell pro-Moscow protests in Ukraine and has warned of “civil wars” in Russia-occupied Crimea, where the separatists hold a majority of the population.