MOSCOW, Nov 28 - President Vladimir Putin on Wednesday shrugged off a threat from U.S. President Donald Trump to cancel a meeting with him due to Moscow's seizure of three Ukrainian navy ships, and accused Ukraine's president of orchestrating the crisis, Reuters reported.

Russia seized the Ukrainian vessels and their crews on Sunday near Crimea, the Ukrainian region which Moscow annexed in 2014, over what it said was their illegal entry into Russian waters, which Ukraine denies.

The episode has raised fears in the West of a wider conflict between the two countries, and Trump said on Tuesday that he might cancel a planned meeting with Putin at the G20 summit in Argentina later this week as a response to "aggression.”

Some of Ukraine's Western allies have also raised the possibility of imposing new sanctions on Russia over the episode, which could deliver a blow to the Russian economy.

But Putin, in his first public comments on the Black Sea incident, said that the Ukrainian vessels had clearly been in the wrong, dismissed the clash as a minor border issue, and accused Ukrainian President Petro Poroshenko of having orchestrated the crisis in order to boost his dire ratings.

Putin said he also still hoped to meet Trump at the G20, while the Kremlin said the meeting was still being prepared and Washington had not informed Moscow it was off.

"It was without doubt a provocation," Putin told a financial forum in Moscow of the incident. "It was organized by the president ahead of the elections. The president is in fifth place ratings-wise and therefore had to do something. It was used as a pretext to introduce martial law."

Putin said the West was willing to forgive Ukrainian politicians because it bought into their anti-Russian narrative.

Trump has been briefed on the situation as he considers whether to cancel the Putin meeting but no decision has been made, White House officials said on Wednesday.

Defense Secretary Jim Mattis said Russia's action shows it cannot be counted on to keep its word.

"It was obviously a flagrant violation of international law. It was, I think, a cavalier use of a force that injured Ukrainian sailors," he told reporters at the Pentagon.

Kyiv has introduced martial law in parts of the country, saying it fears a possible Russian invasion.

Speaking in northern Ukraine, Poroshenko, who has accused Moscow of naked military aggression, talked up his country's readiness to respond to any future Russian military action.

"It's important to keep our powder dry and be ready at any moment to push back the aggressor," said Poroshenko, adding that he had received offers from hundreds of Ukrainian war veterans who said they were ready to return and defend the country. (rt/ez)