Oren Dorell

USA TODAY

Horrific stories emerged Sunday about more than 700 migrants who drowned trying to cross the Mediterranean Sea since Wednesday, according to the United Nations refugee agency.

Rescuers saved 14,000 people at sea last week, by far the highest weekly number yet this year, said William Spindler, a spokesman for the U.N. High Commissioner for Refugees.

"This is by far the busiest week this year in terms of operations, people rescued but also in terms of casualties," Spindler said Sunday.

The rescues involved a flotilla of ships from multiple nations, including Italy, Ireland and Germany, according to The Irish Times.

One incident Thursday involved two overloaded boats, one towing another that didn't have a motor, which smugglers had cut loose when the boat began to disintegrate and take on water, Spindler said.

The motorless boat was loaded with 675 people — and 25 of them jumped off and swam to the other boat. Rescuers later saved another 79 people and pulled 15 bodies from the water, he said. About 550 were missing and presumed dead, he said.

Police in the port city of Pozzallo, Sicily, where survivors were taken, arrested a Sudanese national, Adam Tarik, 29, on smuggling and murder charges, according to Ragusa police patrol chief Nino Ciavola, the Italian newspaper La Stampa reported.

The two old fishing boats had left from the Libyan port of Sabratha, according to La Repubblica,another Italian newspaper. After eight hours at sea, one boat began taking on water, and some passengers jumped. Many drowned, and more died when the tow rope was cut a few minutes later, the newspaper reported. One woman, whose body was later recovered, was almost decapitated by the rope that whipped around after it was cut, the paper said.

Another 100 people are missing from a smuggler's boat that capsized Wednesday, Spindler said. The boat capsized as the Italian navy approached, and passengers moved to the side closest to the approaching rescue ship. Photographs and video of the disaster were captured by Italian sailors and posted to the Internet.

Rescuers also recovered 45 bodies and saved 135 people from a third wreck on Friday, where an unknown number of people are missing, Spindler said.

Survivors were taken to the Italian ports of Taranto and Pozzallo and the Greek island of Lampeduza. One survivor was a 9-month-old girl named Favour, whose mother and father died at sea when their boat capsized, Spindler said. Many Italians have offered to adopt her, he said.

The International Organization on Migration estimates that 194,611 migrants and refugees entered Europe so far this year, with more than 1,475 missing.