The number of migrants at the EU's borders reached a record high of 107,500 in July, officials say, as a sharp surge in expected asylum requests was reported in Germany.

The EU has been struggling to cope with migrant arrivals in recent months.

France and the UK say they will sign a deal to tackle the crisis in Calais.

Over the summer, thousands of migrants have sought to get to the UK through the Channel Tunnel from makeshift camps around the northern French city.

France's Interior Minister Bernard Cazeneuve and his British counterpart, Theresa May, say they will sign a deal there on Thursday to strengthen their countries' co-operation on security, the fight against criminal smugglers, human traffickers, and clandestine immigration.

In early August, the UK pledged to add €10m (£7m) to a fund established in September 2014 to secure the port of Calais, and initially endowed with €15m over three years.

'Third consecutive record'

EU border agency Frontex said the number of migrants surpassed the 100,000 mark in a single month for the first time since it had begun keeping records in 2008.

The Warsaw-based agency said in a statement that the figure of 107,500 migrants for July was the "third consecutive monthly record, jumping well past the previous high of more than 70,000 reached in June".

The German government had earlier forecast that 450,000 asylum seekers could arrive in 2015, but is now set to increase that to 650,000 or higher.

UN High Commissioner for Refugees Antonio Guterres said more countries in Europe should share the burden.

"It is unsustainable in the long run that only two EU countries, Germany and Sweden, take in the majority of refugees," he told German daily Die Welt.

Hungary's southern border marks the edge of the EU's Schengen zone of passport-free travel and is thus a target for migrants seeking to enter the EU.

Its government has said it will send thousands of police officers to its southern border with Serbia in its latest step to stem the flow of migrants.

Source: BBC