For anyone who thought the crisis in Ukraine might start to de-escalate with Viktor Yanukovych gone and Crimea now a de facto part of Russia, the events of the weekend are depressing.

In Donetsk, a large industrial city in Ukraine's east, pro-Russian protesters stormed the regional legislature and, according to reports in Russian media, declared the city "Donetsk People’s Republic" on Monday. The protesters are now demanding a referendum on joining Russia, with May 11 touted as the day of the vote, and calling for "peacekeepers" from Russia to intervene.

Of course, this all looks a little Crimea 2.0. And that's especially worrying, as there have been a number of other reports of pro-Russian protests in other Ukrainian cities like Kharkiv and Luhansk. If Donetsk is following a pattern established by Crimea, it seems these regions might, too.

Crimea is a different place, however. It was, after all, a part of Russia for hundreds of years, only joining Ukraine in 1954. More than 50 percent of its inhabitants spoke Russian, and it had a majority of almost 60 percent ethnic Russians, according to the most recent census (admittedly conducted back in 2001, but still). The region had a long-standing, if not necessarily very effective, pro-Russian independence movement long before Ukraine's current political crisis exploded.

Meanwhile, Donetsk was founded by a Welsh businessman in 1869, a bit of trivia that has prompted a satirical campaign for the region to join the United Kingdom, according to the BBC. It briefly declared itself the Donetsk–Krivoy Rog Soviet Republic in 1918 after the Russian civil war (as referenced by a number of flags seen at protests), but has been a part of Ukraine ever since. While the city does have a slim Russian plurality (48.15 percent vs. 46.65 percent Ukrainians, according to the 2001 census), it's at the center of an oblast with a clear Ukrainian majority (56.9 percent Ukrainians to 38.2 percent Russians, according to the same census).

The different circumstances here may well prompt a different response from Kiev, which offered little more than stern words when Crimea voted for annexation by Russia. (It could certainly be argued that the anger over Crimea's referendum wasn't so much due to Crimea joining Russia, but rather the flawed way the referendum was held.) The Ukrainian government has so far refused to contemplate letting Ukraine's fifth-largest city and a major economic hub secede.

"Yesterday, a second wave of the Russian Federation's special operation against Ukraine started. The goal is to destabilize the situation in the country, topple Ukrainian authorities, disrupt the elections and to tear our country apart," Oleksandr Turchynov, Ukraine's acting president, said in a televised address on Monday. "Enemies of Ukraine are trying to repeat the Crimean scenario but we will not let them do it."