Despite the crisis, Venezuela is holding snap presidential elections on April 22 -- eight months earlier than usual. And even though Maduro has low approval ratings, analysts say a rigged system and a divided opposition likely means he'll win another six-year term.
The government has refused to acknowledge the severity of the problem, often blaming its woes on opposition sabotage and "economic warfare" being waged from Washington. As a result, with little help coming into the country, Venezuelans are being forced to look abroad for food and help.
On Thursday, Santos said that Colombia hadn't been prepared for the mass influx, announcing a raft of new measures to help handle the surge of people.
Along with assigning 3,000 additional officials to deal with Venezuelan migrants, Colombia also quit issuing "border mobility cards" that allowed hundreds of thousands of Venezuelans to move back and forth across the border -- usually to purchase food.
Instead, Venezuelans entering the country for the first time will now need valid passports, a tall order in a country where they're often in short supply or can take months to issue.
Venezuelans already in Colombia will have 90 days to register with government authorities as the country tries to get a clearer picture of the community's situation and needs, Santos said.
In Cucuta, a steamy trade town separated from Venezuela by a river, Santos said authorities were building a temporary shelter that could house 2,000 people in addition to the 250-bed shelter that already exists.
While Arellano and Venezuela's opposition-controlled National Assembly have asked the United Nations High Commissioner for Refugees (UNHCR) to establish more robust, permanent camps in Colombia and Brazil, that's unlikely.
"UNHCR's worldwide policy is that refugee camps should be the last resort and in any case only a temporary measure in response to forced displacement," UNHCR Colombia Representative Jozef Merkx said in a statement. "For UNHCR there are viable alternatives to camps, which include, for example, temporary shelters, rented housing, or even private hosting arrangements."
Even so, the organization is assisting Colombia and Brazil with temporary shelters, where migrants might stay a few days before continuing their journey.