The leaders of Colombia and Venezuela are traveling to Ecuador on Monday in a bid to overcome a monthlong border crisis that has paralyzed trade and movement along the frontier.

President Juan Manuel Santos says he has low expectations for a breakthrough after Venezuela deported more than 1,500 Colombians and closed all land crossings between the two countries.

Meanwhile, Venezuela's Nicolas Maduro said on the eve of the talks that he plans to purchase 12 new Russian fighter jets.

Maduro blames gangs from Colombia for smuggling that he says have led to widespread shortages. Santos has countered that the shortages are a byproduct of failed socialist policies and has sought to rally international opinion against Venezuela for violating the rights of Colombian deportees.