"The soldiers really did participate in a patrol of a section of the Russian-Ukrainian border, crossed it by accident on an unmarked section, and as far as we understand showed no resistance to the armed forces of Ukraine when they were detained," a source in Russia's defence ministry told the RIA Novosti agency.
Ukrainian officials, meanwhile, suspect the Russian soldiers were carrying out a deliberate mission on foreign soil.
The incident came on the same day that the presidents of Russia and Ukraine met face to face in the Belarusan capital, Minsk, for talks aimed at defusing the conflict, which has led to more than 2,000 deaths in five months and raised the specter of full-blown war between the two countries.
The context surrounding this incursion is particularly fraught, not least given the dramatic violence we've seen in recent months, including the downing of Malaysia Airlines Flight 17 by suspected pro-Russian rebels. Earlier this month, Moscow accused Ukraine of sending more than 400 troops into Russian territory; Ukrainian officials countered that rebel artillery fire had forced the soldiers across the border. As the Associated Press reports, accounts of the event differ — a consistent theme during the past year of heated rhetoric between Moscow and Kiev.
It is not unknown, though, for foreign troops to stray into another country genuinely by accident. In 2007, a company of 171 Swiss soldiers performing military exercises marched a mile into neighboring Lichtenstein before realizing that they had taken a wrong turn. "It was all so dark," one Swiss soldier told a local newspaper at the time. The company was carrying automatic assault rifles (in addition to their army knives, of course) but had no ammunition. Swiss artillery fire during a drill in 1985 accidentally landed in the tiny principality, setting a protected forest ablaze. It was a conspicuous moment for the famously neutral Swiss, who had to pay compensation to Lichtenstein.
In 2002, British Royal Marines practiced an amphibious assault in Gibraltar, a long-standing British territory on the tip of the Iberian Peninsula. They stormed a beach while toting 60mm mortars and SA80 assault rifles. But they were met by bemused local fisherman: The British soldiers had landed inadvertently in Spain. Two Spanish police officers appeared and informed the marines of the mistake. "It was clearly an embarrassing and unfortunate incident," a spokesman from the British Defense Ministry told the Guardian. The British troops "made their apologies and left."
More often, though, supposedly "accidental" incidents are the product of border disputes and political tensions. In 2010, the Internet was titillated by the story of how a mistake in Google Maps led Nicaraguan forces to move into a piece of land controlled by neighboring Costa Rica. But that detachment remained, and it took concerted regional diplomatic talks for the two countries to come to an agreement over the disputed territory.
Far more grave are the ceaseless maritime spats in Asia, often involving China, whose expanding navy is widening the scope of its activities, much to the chagrin of many of its neighbors. This week, Japanese officials logged what they claim was the 20th incursion this year by Chinese vessels into waters near the Senkaku islands, uninhabited islets administered by Tokyo but contested by Beijing.
In South Asia, where colonial-era land boundaries are frequently contested, the movements of foreign troop patrols frequently lead to diplomatic flare-ups. Unlike the crisis in Ukraine, though, the governments here have come to accept these episodes as part of the tense but manageable status quo in the region.