...democracy in Europe.
Gasparovic was reacting to the creation of a uniformed guard by a small group of far-right Hungarians last weekend. The guard has also angered Jewish and Roma groups for what they said was its use of Nazi-era symbols.
The guard swore on Saturday to protect Hungary, sparking worries among some Slovaks that militant nationalism could spread over the borders to the half-a-million strong ethnic Hungarian minority in Slovakia.
"History has shown us how fatal forms militant nationalism can develop into if a state is passive and ineffective," Gasparovic told the official Slovak TASR news agency. "It is a warning for all of us."
"I am confident that representatives of Hungary will do everything to prevent such activity from threatening democracy, and that they will make sure that a group like this does not put Hungary in a position unacceptable for the (European) Union, Europe, and the entire world."
Hungarian Prime Minister Ferenc Gyurcsany, the governing Socialist and Free Democrat parties have condemned creation of the guard, which initially consists of only 56 people but has called on more to join.
Relations between the two countries cooled last year after leftist Slovak Prime Minister Robert Fico invited the far-right Slovak National Party, known for harsh rhetoric against ethnic minorities, into his ruling coalition.
Budapest had ruled over its northern neighbour within the Austro-Hungarian empire until its break-up following World War One. Hungary lost two-thirds of its land, including the southern part of Slovakia, and around a third of its population after the war.
[BRATISLAVA/Reuters/Finance.cz]