PARIS — As the southern French city of Nice mourned on Friday for the three people stabbed to death in a suspected terror attack at a church, security has been stepped up at places of worship and schools across France following two similar attacks within two weeks.

France’s interior minister said on Friday more militant attacks on its soil were likely and the country was engaged in a war against Islamist ideology following the second deadly knife attack in its cities in two weeks.

Earlier this month a teacher was beheaded in a Paris suburb after showing controversial cartoons of the Prophet Muhammad to some of his pupils.

Minister Gerald Damarnin was speaking a day after an assailant beheaded a woman and killed two other people in a church in Nice.

The man was shot by police and is now in critical condition in a hospital.

“We are in a war against an enemy that is both inside and outside,” Damarnin told RTL radio. “We need to understand that there have been and there will be other events such as these terrible attacks.”

President Emmanuel Macron has called the deadly stabbing an "Islamist terrorist attack" and announced increased surveillance of churches by France's Sentinelle military patrols, to be bolstered to 7,000 troops from 3,000. Security at schools would also be boosted, he said.

"Quite clearly, it is France that is being attacked," the president added, vowing the country "will not give up on our values".

A 47-year-old man believed to have been in contact with the suspected knifeman has been detained for questioning, a judicial source said on Friday.