A monitoring group says an Islamic extremist group in Nigeria released a video in which its leader praises deadly attacks in Paris last week.

The SITE intelligence group said Wednesday that Boko Haram leader Abubakar Shekau expressed joy over the violence in France in an Arabic-language video that was uploaded to YouTube.

The group, which monitors online postings by Islamic militants, quotes Shekau as saying: "We have felt joy for what befell the people of France in terms of torment, as their blood was spilled inside their country."

It says Shekau often shouts during his eight-minute speech.

Gunmen had attacked the office of French satirical weekly Charlie Hebdo, killing 12. Five other victims died elsewhere in Paris shootings.

Charlie Hebdo had received repeated threats previously for posting Prophet Muhammad caricatures.