Ukraine's foreign minister has become embroiled in an unusual diplomatic row after he was caught on camera making abusive remarks about Vladimir Putin outside the Russian embassy in Kiev on Saturday evening.

As the conflict in eastern Ukraine has deepened in recent months, the chant of "Putin khuilo" has become ever more popular among Ukrainians who blame Russia for stoking discontent in the east. Khuilo is a Russian swearword that approximately translates as "fucker" or "dickhead".

Andriy Deshchytsia, the country's acting foreign minister, arrived at the Russian embassy to reason with crowds who had gathered outside, angered that pro-Russia rebels had brought down a Ukrainian transport plane near Luhansk early on Saturday, killing 49 people on board. The crowds threw rocks and eggs at the embassy, destroyed diplomatic vehicles, and painted swastikas on the gates, chanting "Putin is a fascist" and "Putin khuilo".

Deshchytsia tried to calm some in the crowd, telling them Russia should answer for its actions but that storming the embassy was not the correct response. When he was shouted down by the angry mob, he responded: "I am for you protesting. I am ready to be here with you and say 'Russia, get out of Ukraine'… Yes, Putin is a khuilo, yes."

Seizing on his words, a delighted group of protesters then struck up a "Putin khuilo" chant, leaving the minister looking somewhat bemused.

The incident prompted fury in Moscow, where officials are already incensed by the attack on the embassy and its property.

The Russian foreign minister, Sergei Lavrov, "expressed outrage over the inaction of the Kiev authorities who allowed the rioting outside the Russian embassy" during a phone conversation with his French counterpart, Laurent Fabius, the ministry said.

Alexei Pushkov, a senior Russian foreign policy official, called on the Ukrainian president to fire his foreign minister after the outburst. Leonid Kalashnikov, Pushkov's deputy, told a Russian radio station: "I can't really imagine how anyone, especially a Russian representative, can sit down at the negotiating table with him after such an outburst."

However, Geoff Pyatt, the US ambassador to Ukraine, wrote on Twitter that the minister had been "seeking to defuse a dangerous situation", calling Deshchytsia "a skilled diplomat and credit to Ukraine".

In a sign of how the war of words over Ukraine has intensified online, tThe boss of Kremlin-funded television station Russia Today, Margarita Simonyan, wrote in a caustic response to Pyatt's tweet: "Woah, bad idea for them to legalise grass."

Deshchytsia did not comment on the incident but said on Twitter: "We managed to stop violence at the Russian embassy yesterday, but it will be difficult to do so in future if Russian aggression continues."

Since Petro Poroshenko was inaugurated in Ukraine a week ago after winning last month's presidential election, there has been some hope that the two sides might be able to find a common language. Poroshenko and Putin spoke on the sidelines of the D-Day anniversary commemorations in Normandy, and also on the telephone last week.

But the downing of the plane, killing 40 soldiers and nine crew, has reinvigorated tensions. Poroshenko promised to punish those responsible for bringing the Il-76 plane down. Sunday was declared a day of mourning in Ukraine.

As well as the unrest in east Ukraine, which Kiev says is indirectly backed by Moscow, the two countries are also trying to negotiate a price for gas deliveries. Pushkov claimed Moscow and the EU were looking to solve the gas dispute between Russia and Ukraine but were being stymied by Washington's nefarious plans. "Kiev is blocking any solution so the US has a reason for a cold war," he wrote.