Eikenberry, the former U.S.-led forces commander and serving ambassador to Afghanistan, according to media reports, have held meetings with a number of presidential candidates, including Karzai's main challenger former Foreign Minister Abdullah Abdullah.
"We have no objection if such meetings are for having fair electoral process," Hamidzada said at his weekly press briefing.
However, he said "if during the meetings, candidates' special programs came under discussion or supported, in this case we regard it a violation of Afghanistan national sovereignty."
Hamidzada noted that the issue came under discussion at Ministers' Council meeting and it was decided that ambassadors' wish to meet presidential candidates has to approach through foreign ministry of Afghanistan.
Election campaign for Afghan presidential candidates, which began on June 16, would last until Aug. 17, just 48 hours before the voting begins.