GENEVA - Global migrant deaths have topped 4,000 in the first seven months of this year, a 26-percent increase in the fatality rate compared with the same period of 2015, the International Organization for Migration said Tuesday.

The total of 4,027 migrant deaths this year includes those who perished crossing the Mediterranean as well as others who died on the North African route and at the Turkey-Syria border, according to the Geneva-based IOM.

Some 3,120 people have died since January 1 while trying to cross the Mediterranean Sea. The most deadly route has been the crossing towards Italy, which has cost 2,692 lives, followed by the routes to Greece (383) and Spain (45).

Meanwhile, the British government on Tuesday won its legal appeal against a decision to let four Syrian refugees living in France's "Jungle" camp come to Britain, but they will not be deported.

A British immigration tribunal in January ordered the interior ministry to allow the four to enter Britain while their asylum claims were considered. However, three Court of Appeal judges on Tuesday upheld a challenge by the interior ministry, saying they were "not entirely persuaded" by the justifications used by the tribunal.

The three teenagers and a 26-year old with mental health problems had been living in the sprawling Calais camp for over two months. Under European Union rules, refugees should apply for asylum in the first country they reach, but children and vulnerable adults can transfer their claims to another country if they have relatives legally living there.

Lawyers argued conditions in the camp were "intolerable" and that bureaucratic delays in France meant that the Syrians' applications to live with relatives in Britain were not being processed.

The tribunal agreed that the application should be processed in Britain, and that the four should be allowed to live in the country in the meantime. In January, the four arrived in Britain to a welcome from about 100 pro-refugee demonstrators holding yellow balloons and banners reading "refugees welcome".

They were reunited with their families and two have since been granted refugee status, with the other two cases pending.

The government is not seeking to deport the four but is concerned that the tribunal's decision set a legal precedent.

Campaigners had hoped that the ruling would jolt the government into action, opening the way to relocate more unaccompanied minors from the "Jungle" camp in Calais to Britain.

"It (Tuesday's ruling) means that charities like ours will have to continue identifying children one by one, taking them through a lengthy bureaucratic process as they have to wait to be reunited with their loved ones," George Gabriel, a campaigner with charity Citizens UK, told the Press Association.

"We fear this means many will take the situation into their own hands, choosing between people traffickers on the one hand and train tracks on the other."