Libya's interior ministry has released a statement saying it "fully supports" an anti-government campaign led by an former army general.
However, the interior minister Salih al-Mazig later denied supporting General Khalifa Haftar, who launched his offensive last Friday.
Dozens of state institutions have pledged support for Gen Haftar.
The campaign is seen as the most serious threat yet to Libya's post-Gaddafi government.
Gen Haftar has also called for the toppling of Libya's elected parliament, which his fighters raided on Sunday.
He led an assault against militant groups in Benghazi on Friday, which he accused the government of appeasing. He named the campaign "Libya's Dignity".
The interior ministry praised the operation in a statement posted on its Facebook page.
"We confirm our full support of the will of the people and of the many statements in aid of the Libya's Dignity campaign against terrorism" the statement said.
However, the interior minister Salih al-Mazig appeared shortly afterwards on local television and denied that his ministry had pledged support to Gen Haftar.
He said that he would stand with the "Libyan people" and not with the renegade general.
Libya's interior ministry funds several of the armed groups that have been under attack in the past week.