KYIV, NOV 19 – A dispute over shipping lanes is threatening to reignite the 4-year-old simmering military conflict between Ukraine and Russia following confrontations sparked by both sides in recent days, according to the U.S. News and World Report.

Russian border guards on Monday detained Ukrainian fishing vessels in the Sea of Azov, a strategically important body of water contained to the north by Ukraine, to the west by the Crimean Peninsula and to the east and south by Russia. Monday's incident came days after Russian President Vladimir Putin slammed Kyiv for detaining Russian commercial ships also in the Azov in what he described as "a totally illegal move" and which Kremlin officials have warned may prompt retaliation.

"It's a very deliberate attempt to raise the stakes," Ukrainian Foreign Minister Pavlo Klimkin said Saturday on the sidelines of an international security conference in Halifax, Canada. "It's about creeping annexation of the Azov Sea, but it's also about Crimea."

Crimea came under Russian control in 2014 through what Moscow says was a public referendum but what Kyiv and its Western backers consider an illegal annexation. That same year, Russia began supporting separatist rebels in the eastern Ukrainian region known as Donbas. Klimkin estimates as many as 5,000 Russian forces and 1,500 tanks remain there.

Klimkin said the campaign in the Azov is designed to intimidate Ukraine and to disrupt its economic activities.

Twice last year, Russia shut off access to a key passageway to the Azov known as the Kerch Strait, and its ships have blocked ports in the Ukrainian towns of Berdyansk and Mariupol. The economic disruptions cost Ukraine as much as $40 million each year, according to an analysis by private intelligence firm Stratfor.

Kyiv in 2016 filed a formal grievance to a tribunal in The Hague claiming that Russia's actions violate the 1982 United Nations Convention on the Law of the Sea. The proceedings are ongoing.

Both sides have indicated they're willing to further militarize the region. Ukrainian President Petro Poroshenko pledged in September to build a naval base in the Azov before the end of the year. Kyiv also took possession of two U.S. Coast Guard Island-class cutters earlier this year.

Though it doesn't have any permanent naval bases in the area, Russia has in recent months deployed at least 10 warships and 40 patrol boats to the Azov, Stratfor reports. Senior Russian political leaders have said they have no intentions of boosting the country's military presence there.

Klimkin admits that the Ukrainian military is unmatched to take on Russia's increasingly sophisticated armed forces, but adds that his country is willing to fight back.

"We are very decisive on defending our interests, and we can't let the Russians take up control of the whole Azov Sea," Klimkin said. "The Ukrainian army is not the same army like was the case five years ago. I believe we are prepared." (wr/ez)