PERHAPS one of the biggest obstacles to United Nations' attempts at enforcing an economic embargo against Serb-dominated former Yugoslavia can be found on the streets of this southern Russian city.
The city is full of sanction-busters, but not of the economic sort. Instead volunteers from this region fight, out of a sense of duty, on the side of the Bosnian Serbs.
In many cases, the fighters are Cossacks, Russia's warrior caste under the Czars, who are now struggling to revive their traditions after 70 years of repression by Soviet Communist authorities. Rostov is the major center of the revival effort.
Cossack leaders say Russia's historically close cultural links with Serbia oblige all "true Russian patriots" to aid the "Slavic brother" Serbs, who are battling Muslim forces in Bosnia.
"We have fought, are fighting, and will always fight wherever there is Orthodox Christianity," said Ivan Arkhipov, the acting chief of the Cossacks in the Rostov area.
Though Cossacks may be one of the most actively pro-Serbian elements of Russian society, they are far from alone. The Russian Orthodox Church, among other constituencies, also has been critical of the Russian government's stance on Serbia.
With President Boris Yeltsin under growing domestic pressure from conservatives in the parliament, the administration has moderated its policy regarding Serbia, backing away from outright support of UN sanctions and staking out a more neutral stance.
UN efforts to settle the Bosnian conflict depend greatly on Russia. Moscow can block UN actions by using its veto power in the Security Council, but so far it has refrained from taking such a step. For example, Russia abstained last Saturday in a Security Council decision to tighten economic sanctions against Serbia.
The abstention was the result of domestic political considerations. It aimed to appease constituencies backing Mr. Yeltsin in his power struggle, namely the Cossacks and the Orthodox Church, who support the president more out of the fear of Communist return than belief in his policies.
It also sought to deprive the president's neo-Communist and nationalist opponents of ammunition in their battle for power. That struggle is entering a critical stage with Russia's April 25 nationwide referendum, in which citizens will assess Yeltsin's rule and political and economic policies.
If Yeltsin emerges from the referendum with sufficient popular support, government officials have indicated that Russia's Serbia policy could move back toward coordination with the West.
But in any event, Yeltsin's government will face stiff opposition from the Cossacks, who revile Foreign Minister Andrei Kozyrev as someone "selling out Russia."
"Serbia never betrayed Russia, but now Russia is betraying Serbia," said Ivan, a Cossack who recently returned from a tour of duty in Bosnia, where he fought with Serbs besieging the town of Srebrenica.
IVAN, who declined to give his last name, said the fighting was fierce and the conditions abominable.
"But war is war," he continued. "Cossacks have a different philosophy in this area because we are a warrior people. We perceive war and death in different ways than do other people."
Mr. Arkhipov and others refused to say how many Cossacks have fought for Serbian forces. But government officials say several hundred Russian citizens have fought in the former Yugoslavia over the past year. Authorities say they cannot prevent Russians from going to Serbia, unless they attempt to cross the border carrying weapons.
Ivan, the Cossack, said he volunteered because he felt the Bosnian conflict was a "testing ground" of the West's grand plan "for the further destruction of Russians and the Russian Empire."
"The Serbs are making a stand," he said. "They are spitting on a democratic Russia and a democratic America and I am happy with this."