Attempts by migrants to cross the English Channel -- one of the world's busiest shipping lanes -- have multiplied since October 2018

Britain's Immigration Minister Caroline Nokes said Thursday that a spike in migrants crossing the Channel by boat was "deeply concerning", after dozens of people were rescued overnight.

British border officials found 23 Iranians in three locations in Kent on England's southeast coast early Thursday, hours after French maritime authorities intercepted 11 migrants in a small boat near Sangatte.

"The number of incidents over recent days is deeply concerning," said Nokes.

"Some of this is clearly facilitated by organised crime groups while other attempts appear to be opportunistic."

Nine Iranians, including three children, were the first to be found early Thursday on a beach near the Kent port town of Folkstone, after sailing from northern France in a 13-foot (four-metre) inflatable boat.

Matt Crittenden, of the Littlestone-on-Sea lifeboat station, told AFP its search and rescue helicopter had spotted them and alerted police.

"We realised they were safe and sound, and the police took over," he said.

Britain's interior ministry said each migrant had been given medical assessments.

"All of the adults have been transferred to immigration officials for interview and the three minors have been transferred to the care of social services," it added.

The ministry said two more boats were discovered at around 8:30am (0830 GMT), both near the port of Dover, carrying 14 Iranian males.

It said they had also all received medical checkups and been taken for immigration interviews.

Authorities on both sides of the Channel are worried about the sharp increase in the number of migrants trying to reach Britain by sea.

Attempts to cross the Channel -- one of the world's busiest shipping lanes -- have multiplied since October, with a particular spike recorded over the Christmas period.

British authorities took in 43 people in English waters on Christmas Day and December 26.

Nokes said officials on both sides of the Channel were coordinating efforts through a joint information centre opened in Calais in late November "to tackle criminality at the border".

Attempts by migrants to cross the English Channel -- one of the world's busiest shipping lanes -- have multiplied since October 2018