ROME - European stocks opened trading lower on Monday, with investors spooked by developments in Russia over the weekend.

Although the major indexes on the main European exchanges rallied later in the day, analysts and media reports said the slow start to trading showed that investors remain nervous during a period of geopolitical and economic uncertainty.

Over the weekend, Russia's National Anti-terrorism Committee announced that a counter-terrorist operation regime was introduced around Moscow and in the Voronezh region to prevent possible terrorist acts after Yevgeny Prigozhin -- head of Russia's Wagner private military group -- was accused of attempting to launch an armed rebellion.

Late Saturday, Moscow and Prigozhin reached a compromise following mediation efforts by Belarusian President Alexander Lukashenko. However, on Monday the Russian Prosecutor General's Office said a criminal investigation into Prigozhin's activities had not yet been closed, Sputnik news agency reported.

"The moves Prigozhin made make an already unpredictable situation appear even more unpredictable," Javier Noriega, chief economist with Milan-based investment bank Hildebrandt and Ferrar, told Xinhua. "Market watchers are being especially cautious."

It was evident on Monday that the news around Prigozhin has sent the blue-chip indexes on the European Union's main exchanges lower across the board. When the trading began, some dipped as much as 1 percent. The euro currency also lost value against the US dollar early in the session.

Nevertheless, both measures largely reversed their trajectories later in the day. After starting lower, the main index on the Italian Stock Exchange in Milan rallied to finish up 0.1 percent compared to Friday's close, as did the exchanges in Madrid and Amsterdam. The CAC-40 index in Paris stock exchange was 0.3 percent higher, while in Frankfurt the DAX blue-chip index remained in the red, finishing 0.1 percent lower for the day. Euronext, the broad pan-European stock market conglomerate, lost 1 percent of its value on Monday.

Among specific shares, Italian aerospace company Leonardo closed 4.7 percent down on the day. Carnival PLC on the London Stock Exchange fell 12.1 percent, while food and beverage company Corbion was down 10.7 percent -- all three were among the day's biggest losers.

Yields on major European bonds slid lower on secondary markets as investors sought other options, with the ten-year Germany bond -- Europe's benchmark bond -- losing more than 4 basis points and falling to a 2.31 percent yield.

Investors already have plenty to worry about, according to Noriega, noting that other issues weighing on European economies include high energy prices and inflation, slowing domestic demand in economies, slowing industrial production, and higher interest rates.