DES MOINES, Iowa (Reuters) - At least two people were dead in Kansas and four in Iowa after deadly tornadoes tore through the U.S. Midwest late Wednesday, including one that hit an Iowa boy scout camp where dozens were gathered for a summer retreat, state officials said.

The deadly twisters were among more than 30 that roared through four Midwestern states. One struck the Little Sioux Scout Ranch in western Iowa struck about 6:35 p.m. CDT , killing four and injuring at least 20, authorities said.

Search and rescue operations continued early Thursday after a storm-wracked night.

The tornadoes in Kansas touched down after 10:30 p.m. CDT , ripping through neighborhoods in the northeastern part of that state.

One woman was found dead in the yard outside her home in Chapman, Kansas, and a man was later found dead outside a mobile home in Soldier, Kansas, said state emergency management operations spokeswoman Sharon Watson.

The Kansas twisters injured dozens and destroyed at least 60 homes, authorities said.

In Iowa, 92 campers and 25 adults were attending the Little Sioux camp when the tornado struck, said Tina Potthoff, spokeswoman for the Iowa Emergency Operations Center.

Potthoff said in addition to the four dead, at least 20 and possibly up to 40 people were injured.

Iowa officials said the state National Guard had been mobilized to assist in search and rescue operations, work that was complicated by the heavily treed area where the camp was located and additional lightning strikes and heavy rain.

The scouts had been attending an annual "Pohuk Pride" weeklong junior leader training event at the 1,800-acre ranch, which has four cabin shelters, a 15-acre lake, a rifle range and six hiking trails.

"We are profoundly saddened ... our heart goes out to all of the families and the children affected by this horrific tragedy," said Gov. Chet Culver.

At least two tornado warnings were issued for the Little Sioux area before the twister struck. State officials said they did not know if there were any warning sirens operating at the camp, however.

The tornado was one of more than 30 reported late Wednesday moving across eastern Kansas into Nebraska, Iowa and into Minnesota, according to Storm Prediction Center.

The tornadoes were accompanied by baseball-sized hail and vicious winds, and came in addition to rampant flooding that has forced hundreds from their homes in Iowa.

Culver has declared 54 of Iowa's 99 counties disaster areas due to damage from the flooding and tornadoes. (Additional reporting by Carey Gillam in Kansas City, editing by Philip Barbara)