A large chunk of an Arctic ice shelf has broken free of the northern Canadian coast, scientists say. Nearly 20 sq km (eight sq miles) of ice from the Ward Hunt shelf has split away from Ellesmere Island, according to satellite pictures.
It is thought to be the biggest piece of ice shed in the region since 60 sq km of the nearby Ayles ice shelf broke away in 2005.
Scientists say further splitting could occur during the Arctic summer melt.
The polar north is once again experiencing a rapid ice retreat this year, although many scientists doubt the record minimum extent of 4.3m sq km of sea-ice seen in 2007 will be beaten.
Nonetheless, dramatic changes are occurring in the region, affecting the ice both in the open ocean and the ice which is attached to the coast.
Researchers had predicted that the Ward Hunt ice shelf was likely to experience a major event of this nature.
Scientists travelling with the Canadian armed forces visited the area recently and found major new fractures in the ice that stretched for more 16km.
Ellesmere Island was once bounded by one giant ice shelf that covered almost 10,000 sq km.
Now this expanse of ice has retreated into a string of much smaller, individual shelves, that together cover just under 1,000 sq km.