CALAIS, France: French police said they had prevented more than 1,000 desperate attempts by migrants to get into Britain via the Channel Tunnel Friday, as London vowed further measures to tackle the crisis.

“More than 1,000 attempts were thwarted last night, with around 30 arrests,” the source said, adding there were no reports of migrants injured in their bid to enter the undersea tunnel linking France and Britain.

Police reinforcements appeared to be having an impact, as the number of nightly attempts to penetrate the Eurotunnel premises has roughly halved since its peak at the beginning of the week.

France has sent 120 additional police officers to the northern port city of Calais to stem the crisis, as the number of deaths since June reached 10.

One man died in the early hours of Wednesday, apparently crushed by a lorry as he tried to make it into the tunnel. A spokesman for Eurotunnel said there had been “much less disruption” since the reinforcements arrived to bolster the 300-strong police contingent already stationed in the city.

At least four coaches of riot police were on Friday morning guarding the entrance to the tunnel, where the situation was calm.

A police source said that, while the reinforcements had helped, “the pressure of the migrants is still there” and the “situation remains difficult to deal with.”

However, this source said there had been far fewer migrants managing to enter the Eurotunnel platforms and get on the train shuttles going to England.

During the night, an AFP journalist saw waves of people descend onto the railways close to the Eurotunnel site only to be halted by police.

At least a dozen more made it past the cordon, but ran straight into a second line of officers waiting a hundred meters further down the line.

Around 3,000 people from countries including Syria and Eritrea are camping out in Calais and trying to cross into Britain illegally by clambering on board lorries and trains.

Adding to the Calais difficulties, hundreds of French sailors blocked the city on Friday, using burning tires to prevent access to the port in the midst of the peak holiday travel period.

The roughly 300 workers from French company Scop SeaFrance are protesting against plans to sell off some of their ferries to rival Danish firm DFDS, a move expected to result in hundreds of job losses. The crisis has become a hot political issue on both sides of the Channel and British Prime Minister David Cameron held a meeting of his government’s COBRA emergency committee on Friday on the crisis.

After the meeting, Cameron vowed more security fencing and sniffer dogs to aid French police.

“The situation is not acceptable... We’re going to put in more fencing, more resources, more sniffer dog teams,” Cameron said, warning that the cross-Channel migrants issue would last for the next few months.