The announcement sparked divisions between governments that backed Guaidó, including that of the United States, and Russian government leaders who remain committed to Maduro's presidency.
"People of Venezuela, 90 percent of the armed forces of Venezuela are not with the dictator, they are with the people of Venezuela", General Francisco Yanez of the air force's high command said in a video circulating on Twitter on Saturday.
He told officials: "Do not cross the red line".
The president appealed to the reason of the opposition politicians and said he is ready to meet them "the day they want".
Military is a key pillar of support for the deeply unpopular Maduro. However, he still has no control over the government's institutions or daily governance.
This month's protests, however, have received overwhelming support from overseas, with the U.S., Canada and many others already recognizing Guaido as Venezuela's legitimate leader.
Maduro won a second term in last May's presidential election by a wide margin, but much of the opposition boycotted the process and rejected the result as illegitimate, a stance shared by the United States and numerous nations in Latin America and Europe, reports Efe news. "Russia is not going to bleed for Venezuelan oil".
"As President Trump said just last week: The fight for freedom has begun", Pence said then abruptly had stopped because the room interrupted him with applause and exuberant cheers.
The bloc has agreed to lead an worldwide crisis group of 10 to 12 countries and is expected to hold its first meeting next week in Montevideo, the diplomats said.
The video was tweeted out among Venezuelan journalists and spread from there.
The opposition and a large segment of the global community consider Maduro's reelection fraudulent, in part because the president's most popular adversaries were barred from running.
Previously unknown to the public at large, he has become the standard bearer of the opposition to Maduro, whether on the streets or on social networks.
"For us Venezuelans, there is only one president - President Nicolas Maduro", said Gregory Carrasquel, 35. But he is not the head of state for us, we do not recognize his status.
Pursuant to the request of Interim President Juan Guaido, and in consultation with his officials the United States will mobilize and transport humanitarian aid_medicine, surgical supplies, and nutritional supplements for the people of Venezuela.
At Maduro's rally, supporters blamed the opposition for undermining the Bolivarian Revolution plans through years of protests and seeking financial sanctions against the Venezuelan government.
Guaido explained that aid for Venezuela will include life-saving medicines that are scarce in Venezuela and will be transported by vehicles arriving at several border points, after it is shipped into "friendly ports" in neighboring countries.
"The Kremlin would deny that but the Kremlin does work through private mercenaries", Wigell said, adding that "the Maduro regime doesn't entirely trust its own armed forces anymore".
Guaido later appeared at his building with his wife and daughter, saying "they will not intimidate this family".