Moncef Marzouki travelled to the area to oversee the operation in a signal of its importance.
An Interior Ministry spokesman said there were about a dozen militants in the city of El Kef and about 20 in the remote area of Mount Chambi in the west of the country where police and militants have clashed regularly in recent weeks.
"President Moncef Marzouki arrived in Mount Chambi to raise the morale of soldiers and check on the conduct of pursuit operations there,'' an official in the president's office said.
The Interior Ministry spokesman said security forces had apprehended someone who had been delivering food to some of the suspected militants, cutting them off from supplies.
Tunisia, long among the most secular countries in the Arab world, has become increasingly concerned about attacks the authorities blame on hardline Islamists.
Police say Salafists - Muslim extremists - were behind the assassination of secular opposition politician Chokri Belaid in February, which triggered the biggest street protests in Tunisia since the 2011 overthrow of dictator Zine al-Abidine Ben Ali.
from VOA News