Mugabe also vowed to resist demands by his opponents to reform the country's security forces.
"May I state this clearly and categorically, as Zanu-PF the defence of our sovereignty rests with us and with no other," Mugabe said.
"Any manoeuvres to tamper with the forces will never be entertained by us."
Many senior officers in the security forces fought in Zimbabwe's war of independence and remain loyal to Mugabe.
They have vowed never to recognise Morgan Tsvangirai, prime minister and opposition head, as leader.
Zanu-PF and the MDC are involved in a round of talks to clear outstanding issues of a political deal signed last year.
The MDC wants the central bank governor and attorney general replaced, and party treasurer Roy Bennett and some senior officials sworn-in as deputy agriculture minister and provincial governors, respectively.
Zanu-PF passed a resolution on Saturday rejecting the demands and said, instead, the MDC should call for the removal of Western sanctions and persuade radio stations broadcasting from abroad to stop.
While Mugabe has managed to remain leader of Zanu-PF, a battle is underway over who will eventually succeed him, threatening the future of a party that had enjoyed uninterrupted rule from independence in 1980 till last year.