Islamic State (IS, formerly ISIS), the brutal jihadist terrorist group conquering Iraq and Syria, has released a highly polished new recruitment video partially in German and with English subtitles, targeting jihadist potentials in the West.

The clip, which was posted last Tuesday, features flashy computer generated graphic elements along with modern cinematic techniques, such as lens flares and screen shakes, and has the lyrics to its jihadist theme song jump across the screen.

Images from Iraq and Syria of executions, opening fire on civilian cars and running people, explosions and more are seen in the video. Viewer discretion is advised as the clip contains some graphic imagery.

"Brothers rise up, claim your victory. Let's go, let's go, let's go for jihad," urges the chorus of the propaganda clip, sung in Arabic and German with English subtitles as noted above.

The propaganda in English and German comes as Britain raised its terrorism alert last Friday to the second-highest level, with Prime Minister David Cameron specifying that IS poses the country's greatest ever security risk.

"What we're facing in Iraq now with IS is a greater and deeper threat to our security than we have known before," said Cameron, adding he was "absolutely satisfied that IS...would make specific threats to the UK."

Likewise Germany's domestic intelligence head Hans-Georg Maassen said Sunday of Germans fighting for IS that his state must "expect that these people will return and commit attacks here."

Maassen's agency estimates that no fewer than 400 German citizens have joined IS, and roughly 43,000 Islamists live in Germany.

"There is a link between the successes IS has had so far in Iraq and the activities here in Germany and the propaganda and canvassing activities aimed at young jihadists," added Maassen, noting on the recruitment techniques illustrated in the new video.