U.S. Border agents have found the remains of seven illegal immigrants and rescued eight others so far in July.

The deceased immigrants were found in separate incidents, five in Brooks County, one in Kenedy County and one in Jim Wells County.

Border Patrol officials said the sizzling summer temperatures and rugged ranchlands in South Texas contributed to the deaths.

The rescues happened Wednesday evening at the Falfurrias Checkpoint on Highway 281 North, where agents saved the lives of eight illegal immigrants who were locked inside a refrigerated truck with no means of escape.

Since October 2012, agents have found the remains of nearly 110 illegal immigrants and rescued nearly 430 others.