The Cleveland-based iron ore and metallurgical coal producer slightly lowered its forecast for full-year sales and production volume for U.S. iron ore to 22 million tons because of icy winter weather, which hampered shipments. The new forecast is at the lower end of a previous forecast of 22 million to 23 million tons.

However, it slightly raised its outlook for iron ore sales and production volumes in Eastern Canada and Asia.

The company also trimmed its coal sales and production volume forecast to 7 million tons from between 7 million and 8 million tons because of the potential idling of its Pinnacle mine in West Virginia.

Cliffs shares fell 2 percent in after-hours trade to $15.14.

Cliffs reported a net loss of $2 million, or 1 cent a share, for the second quarter, compared with a profit of $133 million, or 82 cents a share, in the quarter a year earlier.

Excluding one-time items, Cliffs lost 16 per cents per share, Citi analyst Brian Yu said in a note to clients.

That compared with a loss of 8 cents a share that analysts had been expecting, according to Thomson Reuters I/B/E/S.

Revenue fell 26 percent in the quarter to $1.1 billion, on lower prices for iron ore and metallurgical coal, as well as a 24 percent decrease in sales volume from the company's U.S. iron ore operations.

Cliffs Chief Executive Gary Halverson said the company continued to cut costs and reduce capital expenditures in response to a "challenging business climate." Cliffs has been targeted by U.S. hedge fund Casablanca Capital ahead of its July 29 annual meeting, following several quarters of weak earnings and share performance.

Casablanca, which owns 5.2 percent of Cliffs, wants to replace a majority of Cliffs directors, sell assets and replace the company's chief executive.

The company has made a series of concessions to Casablanca, paring its slate of director nominees so that at least four of Casablanca's candidates are likely to win seats, and promising to elect a new chairman after the annual meeting.

(Reporting by Nicole Mordant in Vancouver and Allison Martell in Toronto; Editing by Marguerita Choy and Steve Orlofsky)