By Tim Gaynor
PHOENIX (Reuters) - U.S. border police recovered the bodies of four suspected illegal immigrants who died attempting to cross the remote sun-baked Arizona desert from Mexico in deadly triple digit temperatures over the weekend, authorities said on Monday.
Arizona straddles a busy route for illegal immigrants slipping into the United States from Mexico, many through the Sonora Desert wilderness, where June temperatures peak at above 115 degrees Fahrenheit (46 degrees Celsius).
The U.S. Border Patrol said agents located the bodies of three likely illegal immigrants in separate incidents in the desert south and west of Tucson on Saturday and the body of a fourth on Sunday. All had died of heat exposure.
Agents near Sells, located on the Native American reservation Tohono O'odham Nation, rescued a pregnant, dehydrated Guatemalan woman on Saturday who they found sitting beside the corpse of her husband.
"The couple had crossed the border two days earlier and had been abandoned by their smuggler when the husband collapsed," the Border Patrol's Tucson sector said in a statement.
Later on Saturday, Border Patrol Search, Trauma and Rescue agents found the remains of a second man, believed to be in his early twenties, near the remote village of Queens Well, a few miles east of Sells.
On Saturday evening, agents located a third body near Lukeville, about 150 miles southwest of Tucson. The man, approximately 30-35 years old, was found lying on the ground naked "in an apparent desperate attempt to cool down," the Border Patrol said.
Early on Sunday, agents nabbed a small group of illegal immigrants west of Sells, who told them that a man from their group had fallen behind and died. Agents later found the body of a Mexican man.
Rights group Amnesty International said that from 1998 to 2008, as many as 5,287 migrants perished while trying to cross the nearly 2,000-mile (3,219-km) border with Mexico. Reuters could not verify the figure independently.
Migrant rights groups say a drive to ratchet up security along the frontier in recent years has driven illegal immigrants to take greater risks by trekking further out into the desert to try and beat detection.
During May, Tucson Sector Border Patrol agents said they rescued 61 illegal immigrants compared to 38 during the same time frame last year. A total of 19 illegal immigrants perished in May compared to five during May 2011.
Illegal immigration is a hot-button issue in Arizona, which in 2010 passed a tough law that, among other things, gave police the power to check the immigration status of people they stopped and required immigrants to carry immigration documents at all times.
On Monday, the U.S. Supreme Court upheld the main provision of that law but threw out three other of its provisions, handing a partial victory to the Obama administration, which had challenged the constitutionality of the law.
(Editing by Cynthia Johnston; Editing by Paul Simao)