WASHINGTON (Reuters) - Dozens of protesters gathered on the streets of central Baltimore as US President Donald Trump visited the city for the first time since he called it "disgusting" and "full of rodents" in tweets that sparked heated debate two months ago.

Before Trump spoke on Thursday to House Republicans gathered in the predominantly black city for an annual entertainment meeting, his motorcade was greeted by protesters with banners calling him a rat and ordering him to return to the quagmire.

This came after Trump on Twitter in July attacked Elijah Cummings, an African-American congressman from Baltimore, calling him a "savage bully" who should focus on clearing his "disgusting rat-and-rodent" constituency instead of criticizing him. Immigration officers worked on the Mexican border.

Cummings is chairman of the House Oversight and Reform Commission, has led investigations into Trump and his administration as racist and has strongly criticized his immigration policies.

The powerful lawmaker responded to Trump's tweets by inviting him to tour the city to see the hard work of its residents.