KYIV -- Russian voters in Ukraine were blocked from casting their ballots in Russia's presidential election on March 18, as Ukrainian authorities stepped up security outside diplomatic facilitates and nationalists staged anti-Moscow protests.

Two days prior to the election, in which President Vladimir Putin was heading for a landslide win, Ukrainian authorities announced that only Russian diplomats in Ukraine would be allowed to cast ballots at Russian diplomatic missions.

The move came in retaliation for Russia's annexation of Crimea, which on March 18 voted in a presidential election for the first time since it was taken over in 2014.

Ukrainian police on March 18 guarded the Russian Embassy in Kyiv and consular offices in Odesa, Lviv, and Kharkiv, while nationalist groups protested the election at Russian diplomatic compounds.

Members of Ukrainian national groups gathered on a street near the Russian Embassy in Kyiv, having previously pledged to prevent Russians from voting in the election on Ukrainian territory.

In Kharkiv, Russian nationals came to their consulate in the eastern Ukrainian city but said they were not able to vote. Right-wing activists at the scene brought a mock coffin with an effigy of Putin inside.

One Russian voter in Kharkiv told RFE/RL's Ukrainian Service that he wanted to cast his ballot in the election but was unable to. He said he planned to travel to the Russian city of Belgorod, 80 kilometers away, to vote.

Russia accused Ukraine of violating international norms.

"It is an open interference into the purely domestic affairs of the Russian Federation, which can entail escalation of tension in the already strained bilateral relations," the Russian Foreign Ministry said in a statement quoted by TASS on March 18.

Ukraine's National Police said that there were no major disruptions of public order in the country on March 18.

Millions of ethnic Russians live in Ukraine, but it is unclear how many are registered to vote in Russia.

Ukraine is protesting voting in Crimea, the Ukrainian peninsula seized by Russia exactly four years ago in a referendum largely rejected by the international community as illegitimate. That came just a month after Moscow sent in troops without insignia to secure military bases and other key sites on the peninsula.

Kyiv is also angry with Russia’s support for separatists in eastern Ukraine, where more than 10,300 people have been killed in fighting since April 2014.

Russia's Central Election Commission says that 72,000 Russian citizens have registered with the Russian consulate in Ukraine, Gazeta.ru reported.

France has voiced opposition to the Russian presidential voting in Crimea.

"Challenging borders by force is contrary to international law, including commitments made by the Russian Federation," the French Foreign Ministry said in a statement on March 18.

"Four years after the illegal annexation of the Autonomous Republic of Crimea and [the city of] Sevastopol, France remains firmly attached to the full restoration of Ukraine's sovereignty and territorial integrity within internationally recognized borders," the French statement said.

With reporting by TASS, AP, AFP, and Gazeta.ru