Venezuela's opposition leader Juan Guaido is pushing other countries to consider "all options" for his country at a meeting today in Colombia, after tensions erupted into violence this weekend when Venezuelan citizens marching to the Colombian border to collect humanitarian aid were met with tear gas and rubber bullets fired by officers in riot gear. At least two people were killed and hundreds more were injured.

In Cucuta, Colombia, CBS News correspondent Manuel Bojorquez reports that a bridge connecting Colombia to Venezuela has now been barricaded by forces of President Nicolas Maduro, part of the fierce resistance to a U.S.-backed plan to deliver aid to Venezuela. Leaders across the world are calling for a coordinated effort to get aid in to the country.

Guaido arrived in Colombia's capital yesterday, slamming the border attack as an "unprecedented crime." He will ask leaders during an emergency summit Monday to help bring down the current regime by any means necessary.

Vice President Mike Pence landed in Colombia Monday and met with Colombian President Ivan Duque. Pence is set to meet with Guaido, whom the United States is backing to replace President Maduro. Aside from a military option, Pence is set to announce another measure today: more sanctions against Maduro's government.

But Maduro continues to deny his country is facing a crisis, and has refused to allow aid in, and cut off diplomatic ties with neighboring Colombia for cooperating with what he calls a U.S.-led coup.

"We can't keep putting up with Colombian territory being used for attacks against Venezuela," Maduro said. "Patience is exhausted; I can't bare it anymore"

Secretary of State Mike Pompeo challenged Maduro and his forces to back down, and on Sunday told Fox News the United States would not rule out military force. "Every option is on the table," Pompeo said. "We're going to do the things that need to be done to make sure that democracy reigns."

He characterized Maduro's actions as "the worst of the worst of a tyrant."