GENEVA, Aug. 3 (Xinhua) -- More than 1,500 refugees and migrants have lost their lives attempting to cross the Mediterranean Sea in the first seven months of 2018, the UN refugee agency, UNHCR, said Friday, noting that more must be done to combat smuggler networks.

"The bleak milestone was confirmed after more than 850 lives were lost in June and July alone, marking the Mediterranean crossing as the deadliest sea route in the world," UNHCR said in a statement here.

The agency said it is particularly concerned as the rate of deaths is increasing, despite the total number of people arriving on European shores significantly reduced compared to previous years.

Some 60,000 people have crossed the Mediterranean so far this year, around half as many as during the same period last year, and a return to pre-2014 levels. said UNHCR.

However, one in every 31 people attempting the crossing in June and July died or are missing, compared to one in 49 during 2017.

"UNHCR urges States and authorities along transit routes to take all necessary action to dismantle and disrupt smuggler networks," said Vincent Cochetel, UNHCR special envoy for the Mediterranean.

He said that to save lives at sea, appropriate measures must be used to hold to account those who seek to gain profit from the exploitation of vulnerable human beings.

Refugees fleeing Syria make up around 13.5 percent of new sea arrivals in Europe, the largest nationality group, said UNHCR.

Cochetel said exploitative traffickers and smugglers are reportedly organizing increasingly dangerous crossings, in ever-more unseaworthy and flimsy vessels.

The boats, which smugglers severely overload with passengers, are then left to sail out at sea in the hope that a rescue will come in time.

"Without further action, more people are expected to perish at sea in the months ahead, as traffickers look to exploit the opportunities offered by improved weather conditions," said UNHCR.

The refugee agency said that unlike in previous years when Italy received the majority of new arrivals, Spain has become the primary destination, with more than 23,500 people arriving by sea, compared to around 18,500 in Italy and 16,000 in Greece.