Texas Gov. Greg Abbott activated the entire Texas National Guard as Houston deals with devastating flooding after Hurricane Harvey, deploying 12,000 total guardsmen to assist in rescue efforts, his office said Monday.

"It is imperative that we do everything possible to protect the lives and safety of people across the state of Texas as we continue to face the aftermath of this storm," Abbott said in a statement. "The Texas National Guard is working closely with FEMA and federal troops to respond urgently to the growing needs of Texans who have fallen victim to Hurricane Harvey, and the activation of the entire Guard will assist in the efforts already underway."

The Texas Guard currently has activated and mobilized roughly 3,000 personnel to assist with rescue and recovery operations related to Hurricane Harvey.

"The men and women of the Texas National Guard are working around the clock to support all relief efforts from Hurricane Harvey," Maj. Gen. John F. Nichols, Texas Adjutant General, said in a statement. "We will not rest until we have made every effort to rescue all those in harm's way. We will remain here as long as we are needed. I want to thank Governor Abbott for his continued leadership and look forward to serving the great people of Texas."

More than 30 inches of rain has fallen in parts of Harris County, Texas, which includes Houston, in the last 72 hours, the National Weather Service said Monday. Peak flooding is expected Wednesday and Thursday.

Hurricane Harvey made landfall on Friday and into Saturday, and downgraded to a tropical storm. But parts of southeastern Texas have experienced catastrophic flooding in the wake of the storm.

FEMA Administrator Brock Long said he expects more than 30,000 people to be placed into temporary shelters, and 450,000 to file for assistance as a result of the storm.

Federal, state and local authorities have been working to rescue thousands of people from rising floodwaters, with efforts focused on rescue operations.