France increasing security after attacks

France is stepping up security after three days of violent lone-wolf attacks.

The incidents have left about 30 wounded and reignited fears of attacks by Islamist radicals.

French Prime Minister Manuel Valls says the country faces a terrorist threat.

(SOUNDBITE) (French) FRENCH PRIME MINISTER, MANUEL VALLS, SAYING:

"There is, as you know, a terrorist threat to France. We -- along with the Interior Minister -- have been saying it for a long time. It's without a doubt, the major challenge of our times."

The most recent attack came Monday night in Nantes where a man plowed his van into a crowded Christmas market, injuring at least 10 people.

On Saturday a stabbing wounded three police officers, and on Sunday another man drove into crowds.

In these first two incidents, the perpetrators yelled "Allahu Akbar".

Valls says investigating the attacks is a top priority.

(SOUNDBITE) (French) FRENCH PRIME MINISTER, MANUEL VALLS, SAYING:

"Th