French President Emmanuel Macron said the EU's Schengen area, which allows people to cross borders freely, may need reform, the BBC reported on Thursday.

A knife attack in Nice last week, which killed three people, was blamed on a Tunisian migrant who crossed into France from Italy in October.

It was the second alleged jihadist attack in France in just over a month.

France's security alert is at its highest level, with thousands of soldiers deployed to protect places of worship and schools, since teacher Samuel Paty was beheaded for showing cartoons depicting the Prophet Muhammad to his students.

President Macron has since sparked anger and protests in some Muslim-majority countries with his robust defence of France's values and freedoms that permitted the publication of cartoons.

But he has rejected right-wing calls for greater safeguards to protect the country's principle of secularism, saying: "The situation does not warrant changing the constitution."

And, in a letter to the Financial Times, he made clear France was fighting "Islamist separatism, never Islam". He accused the British newspaper of misquoting him in an article - which has since been removed from its website - suggesting he was "stigmatising French Muslims for electoral purposes".

"I will not allow anybody to claim that France, or its government, is fostering racism against Muslims," he said in the letter to the editor.

Speaking during a visit to the French-Spanish border, Macron said he would be doubling police border patrol numbers from 2,400 to 4,800 "because of the worsening of the threat" of terrorism.

He also said he would be unveiling proposals for strengthening border security within the EU at the next EU summit in December, which would include "intensifying our common border protection with a real security force at the external borders".

Under the Schengen agreement, people within the EU are able to pass freely across borders without showing their passport. However, border checks have made a return in recent months because of the coronavirus pandemic.