Migrants make their way along train tracks as they attempt to access the Channel Tunnel in Frethun, near Calais, France Wednesday. (Pascal Rossignol/Reuters)

France has deployed more than 100 riot police officers to Calais to bolster security as hundreds of migrants have been trying night after night to rush the railway tunnel leading to England — at times with fatal consequences.

One migrant was crushed to death Wednesday during an attempt to breach security. Such attempts, numbering in the tens of thousands, have fueled a growing sense of crisis on the English Channel this year. The 30-mile Channel Tunnel, often referred to as the Chunnel, is used by passenger trains and freight services to connect France and Britain.

Another migrant was in critical condition after being electrocuted during an attempt to jump on a Eurostar train in Paris headed to London.

These migrants pressing northward are fleeing war, dictatorship and poverty in Africa and the Middle East. They tend to spend as little time as possible in their southern European landing spots such as Italy, where two ships unloaded Wednesday, one carrying 435 passengers and 14 bodies and another with 692 migrants.

British officials have increasingly sounded the alarm over a potential influx of foreigners. French officials, meanwhile, are concerned about approximately 3,000 migrants in mostly lawless encampments scattered in the Calais area.

French gendarmes block migrants along a road to prevent them access to train tracks which lead to the Channel Tunnel in Frethun, near Calais, France Wednesday. (Pascal Rossignol/Reuters)

It is not clear how many migrants ever reach Britain, although a few succeeded this week in stowing aboard trains to make the 35-minute trip.

France sent 120 riot police officers to Calais to increase security, which British authorities say has been lax. France’s government called on Eurotunnel, the company that operates the tunnel, to increase its protection of the sensitive site.

Eurotunnel defended its efforts, saying Wednesday that it had blocked more than 37,000 attempted security breaches since January. Nine people have died trying since June.

There were wildly conflicting estimates of the people involved in Wednesday’s rush for the tunnel, from 150 to as many as 1,200.

The attempts have been increasing exponentially as has the sense of crisis in recent weeks, spurred by new barriers around the Eurotunnel site, lack of access to the Calais port, labor strife that turned the rails into protest sites for striking workers, and an influx of desperate migrants.

epa04865519 Migrants walk along the railway to catch a train to reach England, in Calais, France Wedensday. (Yoan Valat/EPA)

The British government has agreed to provide an extra $11 million in funds for measures to improve security at Calais. Until Wednesday, 60 French police officers guarded the site, along with Eurotunnel security crews.