In a speech at Venezuela's Central University, he said police had visited his family home looking for his wife.

Mr Guaidó declared himself president this month and was immediately recognised by the US and several Latin American countries.

Russia and China back President Nicolás Maduro.

Military support is seen as crucial to Mr Maduro's hold on power. But Mr Guaidó says he has held secret meetings with the military to win support for ousting Mr Maduro.

Protests have been held across the country since Mr Maduro began his second term on 10 January. He was elected last year during a controversial vote in which many opposition candidates were barred from running, or jailed.

About three million people have fled Venezuela amid acute economic problems.

"Right now, special forces were at my home asking for Fabiana," said the opposition leader during a speech at the university.

"The dictatorship thinks they will frighten us. I received this information before I came here. But I didn't start with that. I started with a plan for all Venezuelans."

Addressing security forces directly, he said: "I will hold you responsible for any intimidation of my baby, who is just 20 months old."