Algeria's army has reinforced its forces along the eastern border with Tunisia, Interior Minister Daho Ould Kablia said, days after the killing of eight Tunisian soldiers.
The soldiers were found on Monday with their throats cut after being ambushed by fighters in Mount Chaambi, an area near the border with Algeria.
Algeria's army "reinforced its resources and capabilities on the eastern border of the country because of the troubles that Tunisia is going through," Kablia told the national news agency APS on Thursday.
Tunisian troops have intensified their hunt for an armed group in the Mount Chaambi area since the spring, after several members of the security forces were killed or wounded by explosive devices.
Algiers has said it strongly condemns "the base act of terrorism that resulted in several deaths among the Tunisian armed forces".
Islamist groups in Algeria remain active decades after a bloody civil war in the 1990s that killed some 200,000 people, leading some in Tunisia to suggest connections with the group in Mount Chaambi.
Algeria's foreign ministry condemned on Thursday what it said were "false allegations" against Algeria from "certain circles in Tunisia".
In a statement, ministry spokesman Amar Belani decried the allegations as a move to "deceive the Tunisian people as they are mobilising to unite against terrorism."
Interior Minister Kablia said there had been an "exchange of security information between Algeria and its neighbours to fight the various scourges that threaten the security and stability of the region".
Exchange visits by senior officials from Tunisia, Libya and Algeria have led to closer cross-border cooperation.
Separately, the defence ministry issued a rare communique in which it said that a heavy machinegun, two rifles, ammunition and a number RPG-7 rockets were found in two 4X4 vehicles on Thursday, near the Libyan border.