President Donald Trump claimed tonight Democrats were encouraging caravans of migrants to "violate our laws and to break into our country."

“As we speak, the Democrat Party is openly encouraging caravan after caravan of illegal aliens to violate our laws and to break into our country,” Trump told the Wisconsin crowd.

He emphasized that this is a “crisis on the border” and continued to blame Democrats for immigration policies in the US.

“Right now is the sole result of Democrat laws and activist Democrat judges that do whatever they want and that prevent us from returning illegal aliens back home to Central America and other parts of the world.”

Some background: US officials have been keeping their eyes on a caravan that's forming in El Salvador, a Department of Homeland Security official told CNN on Tuesday. And another migrant caravan of around 2,000 people entered Guatemala from Honduras and is expected to reach Guatemala City on Wednesday.

US-bound migrant caravans are not uncommon, as Central Americans desperate to escape violence and poverty band together for safety on the road. Some advocates also use the mass movements to help draw attention to political causes.

But the formation of new caravans in Central America comes as political pressure mounts over a convoy of thousands of people now transiting Mexico, en route from Honduras to the United States.

That caravan has drawn the ire of the President, who in an apparent fear campaign aimed at boosting turnout in the November 6 midterm elections. Trump has blamed Democrats, without evidence, for pushing for overrun borders.