Friday their response gained an edge, when Ukrainian President Petro Poroshenko tweeted that Russians aged 16 to 60 would be barred from entering Ukraine, the most concrete measure taken yet by Kiev during the 30 days of the martial law they have declared.
Ukraine's state security service said it raided the residence of a senior Russian-backed Orthodox priest on Friday, who heads one of the country's holiest sites, citing a clause in the criminal code relating to whipping up religious hatred.
The Kremlin said it still expected the Putin-Trump meeting to take place and played down the threat of cancellation, with foreign policy advisor Yuri Ushakov saying: "The meeting is equally needed by both sides".
"Those who have such opportunities could help by exerting influence on the Ukrainian authorities", Peskov said.
Ukrainian officials on Friday upped the ante in the growing confrontation with Russia, announcing a travel ban for most Russian males and searching the home of an influential cleric of the Russian Orthodox Church.
The Ukrainian Navy has accused Russian Federation of firing on and capturing three of its ships near the Kerch Strait, a narrow sea passage close to the Crimean peninsula that separates the Black Sea and the Sea of Azov, Nov. 25, 2018.
The United States and the European Union have imposed sanctions on Russia since 2014, when Moscow annexed Crimea after a pro-Russian leader was toppled in Kiev. But, by asserting that the vessels entered Russian waters illegally, not to mention escalating tensions with the West, Putin may be hoping to breathe new life into the siege narrative, thereby inspiring the kind of primitive patriotism on which he has long relied. The Russians are already prone to complaining about North Atlantic Treaty Organisation buildups along their borders and would likely object to even the boost of Black Sea naval deployments suggested by the BBC.
Moscow fired on and seized three Ukranian gunboats and said three sailors were injured, while Kyiv said six were wounded.
"Putin wants the old Russian empire back".
Overall, 35 vessels have been prevented from carrying out normal operations and only vessels moving towards Russian ports on the Azov Sea are permitted entry, he said on Facebook.
For his part, Ukrainian President Petro Poroshenko warned that there is a threat of a full-blown war with Russian Federation. The rogue vessels were blocked by Russian border guard ships, rammed, shot at and eventually seized.
"Based on the fact that the ships and sailors have not been returned to Ukraine from Russian Federation, I have decided it would be best for all parties concerned to cancel my previously scheduled meeting in Argentina with President Vladimir Putin".
The EU has propped up Ukraine's war-scarred economy since the Crimea annexation while prodding the pro-Western authorities to pass reforms and tackle corruption.
On Thursday, US President Donald Trump canceled his planned meeting with Russian leader Vladimir Putin because of this crisis.
The seamen are still being kept behind bars pending an investigation.
Russia is calling on the United Nations, the OSCE, the Council of Europe and other global organizations to pay attention to violations of human rights in that country, Russian Foreign Ministry spokesperson Maria Zakharova said on Friday.
There are rumblings that Ukraine will call for the closure of the Bosphorus Strait to Russian Navy traffic as a result of Moscow's recent acts, which would cut off the Black Sea Fleet from the Mediterranean.
Moscow contends that Ukraine deliberately violated the new rules of transit that Kiev had previously observed, to create an incident.