The incident comes before a G20 meeting in Brazil this weekend where Russian President Vladimir Putin could meet with President Donald Trump, who said Monday that he didn't like the situation, but refused to condemn the aggression.
It makes it unlikely that Trump will put pressure on his Russian counterpart at the G20 summit to ease up on Ukraine, given the president's present and past reluctance to openly criticize Russia. So far, Trump seems content to let Europe handle the situation, remarking Monday that European leaders were "working on the situation," Reuters reported.
The U.S. ambassador to the United Nations, Nikki Haley, was stronger in her criticism, calling Russia's action an "outrageous violation of sovereign Ukrainian territory" and said such "outlaw actions" made it hard for the U.S. to have a normal relationship with Russia.
European Council President Donald Tusk took to Twitter on Tuesday to condemn the action and called on Russia to release the ships and sailors. Russia has so far refused to do so.
The U.S. and European Union currently have sanctions on Russia in place for its 2014 annexation of Crimea from Ukraine, as well as its role in a pro-Russian uprising in the east of the country, although Russia denied involvement in this.
The EU must decide soon whether to extend those sanctions, which have seen asset freezes and travel bans on individuals alleged to have assisted in the annexation and sectoral sanctions in Russia.
In September, the EU extended Ukraine-related sanctions on 155 persons and 44 entities until March, saying that its "assessment of the situation did not justify a change in the sanctions regime." A separate series of European Ukraine-related sanctions targeting specific sectors of the Russian economy are in place until January and there are sanctions on Crimea itself until June. Likewise, the U.S.' Ukraine-related economic sanctions on Russia are in place until March.
Eurasia Group's Brideau said more sanctions were now likely. "The most that Washington and Brussels are likely to impose at this stage is more sanctions against individuals and entities. Stronger sanctions that might target new economic sectors or major Russian oligarchs are unlikely unless the episode escalates," he said.
"New fighting would make sanctions escalation more likely but, even in this case, the potential for much stronger action against sovereign debt or Russian crude oil exports would remain low."