"We have increasing numbers of people reaching the [south] borderline and as a matter of fact they are coming in groups, in the past we were not used to receiving many groups of people, and unaccompanied children", Peralta said on the sidelines of the St. Petersburg International Economic Forum (SPIEF).
Peralta added that immigrants were coming mostly from Honduras, Guatemala, El Salvador, Nicaragua and Venezuela.
The statement comes a day after Mexico announced that it would send 6,000 National Guard troops to its southern border with Guatemala to respond to the inflow of illegal immigrants wanting to reach the United States, as part of the US-Mexican agreement on immigration measures.
An increasing number of migrants from Central America have been arriving at the US border with Mexico in recent months. Trump has called the surge of arrivals a crisis and declared a national emergency in February to secure funds to build a border wall.
SPIEF is an annual Russian business event held in St. Petersburg since 1997.