Sweltering in 19 straight days of 100-degree heat, Fort Worth was hit with another discomfort Friday when a main break forced the city's 450,000 residents to cut back on water.

Fort Worth officials ordered all residents to eliminate outdoor water use and cut back on indoor use after a major main broke Thursday. Those who refused to follow orders risked trouble."If people do not comply, we do have the ability under ordinance to shut off their water," Water Department spokeswoman Mary Gugliuzza said.

The heat wave that has broiled the Deep South and many spots across the country has been blamed for at least 140 heat-related deaths since May. Texas has gotten the worst of it with 92 deaths. Louisiana has reported 26 deaths and Oklahoma 15.

Officials at the Del Rio sector of the U.S. Border Patrol on Friday confirmed that three more immigrants died this week in Texas, bringing to 50 the number who have died trying to cross the border from Mexico.

Things were not expected to cool down over the weekend.

The National Weather Service forecast for Texas is "hot, hot, dry, same old same old," meteorologist Krista Villarreal said. Temperatures should remain around 100, she said.

In Oklahoma the temperatures hit 106 in Oklahoma City, tying a record set in 1943.

The heat took its toll on 480 troops from an engineering battalion at work on a construction project at the Army Ammunition Plant near McAlester. Twenty heat-related injuries were reported.