Venezuelan opposition leader Juan Guaido has told a huge rally of supporters that humanitarian aid would enter the country on February 23, setting the stage for a showdown with President Nicolas Maduro who has refused to let supplies in.
Tens of thousands of Venezuelans protested in the streets nationwide on Tuesday to demand that Maduro allow aid into the country, where food and medicine shortages are rife.
Guaido invoked a constitutional provision to assume the presidency three weeks ago, arguing that Maduro's re-election last year was a sham.
Most Western countries, including the United States, have recognised Guaido as Venezuela's legitimate president, but Maduro retains the backing of Russia and China as well as control of state institutions including the military.
An aid convoy supplied by the US and Colombia arrived in the Colombian border town of Cucuta last week, where it is being held in warehouses. A Venezuelan opposition envoy has also said Brazil's government would try to get humanitarian aid to the border.
Maduro has denounced the aid as a US-orchestrated show to overthrow his socialist government and said it will not be let into the country. He has demanded instead that Washington lift economic sanctions.
On Tuesday, Guaido said he was issuing a "direct order" to the armed forces to allow the aid in, though so far there are not clear signs the military will disobey Maduro.
Guaido did not specify from where aid would enter, but said the opposition would go in a convoy to safeguard the supplies.
"Put yourselves on the side of the constitution, but also on the side of humanity," Guaido said, in a message directed at the military.
"February 23 will be the day for the humanitarian aid to enter Venezuela, so from today we will have to get organised."
Guaido, who has galvanised the opposition after several years of in-fighting and government crackdowns, vows to keep calling protests to pressure Maduro to step down so new presidential elections can be held.
Meanwhile, Russia has said it is ready to facilitate the start of dialogue between Venezuela's government and opposition but warned the US against intervening in Caracas' internal affairs.
"We have been maintaining very important contacts with the government of this country and stand ready to provide a kind service in order to facilitate the process of finding ways out of the situation," Tass news agency quoted Russian Deputy Foreign Minister Sergei Ryabkov.
He also said Russia had made some proposals to Venezuela on settling its crisis but gave no details.
Moscow has invested billions of dollars into Venezuela's economy and oil production.
