PARIS (Reuters) - Hundreds more migrants have made their way to Calais on France’s north coast in recent months despite the bulldozing of part of their “jungle” camp in March, and despite extra port security aimed at stopping them from reaching Britain.

A migrant walks past makeshift shelters in the northern area on the final day of the dismantlement of the southern part of the camp called the 'Jungle" in Calais, France, March 16, 2016. REUTERS/Pascal Rossignol

Official figures from the Pas de Calais region put the total in tents, shanties and a new state-run city of converted shipping containers at 3,900, up from 3,500 at the end of March, but well down from the peak of over 6,000 reported in September.

And according to local aid organizations - who have long been at odds with the official count - numbers in the camp are much higher at somewhere between 5,000 and 7,000 people, of whom several hundred are unaccompanied children and teenagers.

“We still see people arrive, the situation on the ground remains very difficult for refugees and specifically children,” Marianne Humbersot, a lawyer who offers counseling for migrants, said.

Many of the migrants fleeing war and poverty in the Middle East, Africa and elsewhere still try reach Britain, where they hope to resettle, either by climbing onto lorries heading onto ferries or by breaking into the nearby Channel Tunnel.

These efforts are in spite of additional UK-funded security measures introduced in October including extra fencing, cameras and hundreds of additional police officers.

The camp itself has changed shape significantly this year.

A state-run park of converted shipping containers with capacity for 1,500 beds opened in January in the north of the jungle area. The southern half was cleared two months ago.

In another part of the northern section, migrants have been invited to move into dozens of large heated tents.

Refugees have also been encouraged to leave the area by bus for one of France’s 136 reception facilities. A Pas de Calais spokesman said almost 4,000 refugees had traveled to these reception centers since November last year.