Addressing reporters in Baku, Qaralov said his office had collected evidence showing that some "radical forces" were contemplating seizing power through unconstitutional means.
Qaralov gave no further details, but warned that any attempt at toppling President Ilham Aliyev's government would be met "adequately." Tensions are running high in Azerbaijan ahead of the 6 November legislative elections.
Security forces earlier this month arrested the leader of the opposition Yeni Fikir (New Thinking) youth movement, on charges of plotting against the government with the help of foreign money.
The arrest of Ruslan Basirli triggered a wave of pro-government rallies against the opposition Azerbaijan's Popular Front Party, which is suspected of links with Yeni Fikir. The opposition has denounced a provocation to call off the elections.
For RFE/RL's coverage of events in Azerbaijan, see "News and Features On Azerbaijan"