More leaders from across the political divide have also come out in condemnation of recent remarks by Public Affairs Cabinet Secretary Geoffery Ruku
Ortega said future governments would be safeguarded through new laws designed to prevent what he described as foreign-backed attempts to unseat his administration.
Liibaan pledged to prioritise peace, reconciliation, security and inclusive economic development if elected.
The government has confirmed hackers took over the President's official website on Saturday, defacing its homepage and demanding a Sh41.3 million ransom.
President William Ruto's official website, president.go.ke, was down on Saturday after hackers allegedly took control of the homepage and replaced it with a ransom message.
Osman Mohamed Adawe officially declared his candidacy by unveiling an ambitious agenda centred on security, reconciliation and economic transformation.