At least seven people have died so far and hundreds are still stranded in and around Houston as heavy rain caused by Hurricane Harvey continued to pound Texas in the United States, reported Reuters. Of the seven dead, six have died in Harris County, where Houston is located. A 60-year-old woman also died in neighboring Montgomery County when a tree fell on her house when she was asleep.

Officials have warned that floodwaters in Houston are likely to rise, and would drive tens of thousands more from their homes. National Guard troops, police officers, rescue workers and civilians used helicopters, boats and special trucks on Monday to rescue the stranded people.

“The Coast Guard is continuing to receive upwards of 1,000 calls per hour,” US Coast Guard Lieutenant Mike Hart told CNN. “Today [Monday] alone, the Coast Guard has rescued over 3,000 people. That includes both air rescues and rescues using boats.” The National Weather Service has also issued several flood warnings in the region.

US President Donald Trump is set to visit Texas on Tuesday. He may also visit the US state of Louisiana, where the hurricane has triggered massive rainfall. The president has signed disaster proclamations for Texas and Louisiana, paving the way for the US Congress to provide flood relief measures.