By Jeremy Diamond, CNN

(CNN) -- President Donald Trump, speaking Monday alongside the President of Nigeria, derided US immigration laws as "weak," "pathetic" and "obsolete."

"Just look at our southern border and look at our weak and obsolete immigration laws. And they are obsolete and they are weak and they are pathetic," Trump said. "And there's no country in the world that has laws like we do and they've got to change and they've got to change now for the safety of our country."

Trump's comment came as he discussed loopholes in US immigration laws that he said can be exploited by terrorists and traffickers -- but it also comes as his administration is keeping a close eye on the arrival of the migrant caravan at the US-Mexican border.