President Donald Trump signed a disaster declaration to send emergency relief as families and search teams continue to look for missing loved ones.

A Christian girls' summer camp in central Texas said on Monday that at least 27 campers and counselors were among those who perished in the catastrophic flooding over the July 4 weekend, while emergency responders still searching for dozens of missing people faced the prospect of more heavy rains and thunderstorms.

Emergency responders continue to search for missing people and local police said efforts have been slowed by "sightseers who are making things worse."