Donald Trump is to visit the sites of mass shootings in Ohio and Texas amid warnings he will not be welcome.
The attacks in El Paso, where Hispanic people appear to have been targeted, and Dayton left 31 people dead.
Before leaving for Ohio, he said he was concerned about “the rise of any group of hate… whether it’s white supremacy, whether it’s any other kind of supremacy, whether it’s Antifa”.
However, he has been accused of stoking hatred against Hispanic communities.
The Democratic congresswoman who represents El Paso, Veronica Escobar, is refusing to meet him, saying his “racist and hateful words & actions” had caused pain to her community and her country.
The El Paso shooting is being treated as a possible hate crime. Much of the city identifies as Hispanic or Latino and the suspect is thought to be the author of a text posted online which said “this attack is a response to the Hispanic invasion of Texas”.
The text echoed some of the US president’s language, with Mr Trump having frequently used the term “invasion” to describe the situation on the US-Mexico border.
Police have still to establish a conclusive motive for the Dayton attack but say they have uncovered evidence “that the shooter was exploring violent ideologies”.
Attempts by Mr Trump and others to link the shootings to mental illness have been criticised by healthcare professionals.
On Wednesday, the president said he did not “want guns in the hands of sick people” and was “looking to do background checks”.
He could face protests in Dayton where Mayor Nan Whaley, a Democrat, has urged people to “stand up”.
In El Paso, Beto O’Rourke, a native of the city and Democratic presidential hopeful, said Mr Trump had “no place” there.
Both he and Ms Escobar have said they will attend a community event intended to honour those who died and “confront white supremacy”.
In a tweet on Tuesday night, the president mocked Mr O’Rourke’s Spanish nickname, “Beto” and suggested he should “be quiet”. The Irish congressman’s birth name is Robert, but he was given the nickname as a child as he has the same name as his grandfather.