A migrant has died trying to reach the United Kingdom through the Channel Tunnel, a French official in the Pas-de-Calais region has said.

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One of six sections of the tunnel was closed for investigation after Tuesday's incident and it was not yet clear how the death had occurred.

A Eurostar train was stopped at the entrance to the tunnel on the way to Britain, the AFP news agency reported.

"Following the discovery of migrants on a freight shuttle early this morning, the shuttle was immediately stopped," the French official said.

"During an investigation by border police, a deceased migrant was found in the tunnel."

Although traffic was only briefly interrupted in the tunnel, the incident triggered three-hour delays on the British side and an hour on the French, according to operator Eurotunnel.

On Friday, traffic along the tunnel was disrupted when dozens of migrants attempted to breach a restricted area, according to officials.

About 3,000 migrants, mostly from Africa and the Middle East, are camped around the northern French port in the hope of reaching Britain.

In 2014, French riot police cleared three campsites housing hundreds of immigrants in Calais.

Source: AFP