The market is seeing few signs of a turn-around from Blackberry.

The Waterloo, Ontario based smartphone maker has issued an  unexpected quarterly operating loss.

BlackBerry shares tumbled about 28 percent in both Toronto and  U.S. trading.

The company  has struggled to compete against Apple’s  iPhone, Samsung’s Galaxy phones and other devices powered by Google’s Android operating system.

Blackberry  said smartphone sales were up 13 percent from the previous quarter, a period when buyers waited for the BB10 phones to hit the market.

But deliveries are down from a year ago as sales of its older line of BlackBerry devices taper off.

Excluding one-time items such as the cost of job cuts, BlackBerry reported a loss from continuing operations of $67 million  or 13 cents a share, on revenue of $3.1 billion.

Analysts, on average, expected a profit of 6 cents a share, on revenue of $3.36 billion.

Earnings were also reduced about 10 cents a share due to Venezuelan currency restrictions.

Blackberry says  it shipped 6.8 million smartphones in the quarter. On a conference call it said 40 percent of them, or 2.72 million devices, were BlackBerry 10 devices. Analysts looked for shipments of about 3 million of the new phones.

It reported a net loss of $84 million, or 16 cents a share, in the fiscal first quarter ended June 1. That compared with a year-earlier loss of $518 million, or 99 cents a share.

BlackBerry did not provide a detailed outlook for the rest of the year, saying the smartphone market remained highly competitive, making it difficult to estimate units, revenue and levels of profitability. It also said it would not supply subscriber numbers due to changes in its revenue model.