Berlin/Washington  - At least 30 German Islamists have visited paramilitary training camps in Pakistan this year, a US newspaper reported Monday.

Of these, around ten had already returned to Germany, according to an article in the Washington Post, citing German security sources.

As a result, worries had grown over the possibility of new terror attacks in Europe, the paper reported, quoting a high-ranking German terrorism expert who said the situation was serious.

A German interior ministry spokesman refused to comment on the article, but said it was known that German Islamists were travelling to Pakistan for training. These movements were being monitored, the spokesman added.

Several groups linked to radical Islamist operations such as the Taliban and al-Qaida were recruiting in Germany, German officials told the paper. Since these organizations were working independently, it was difficult to investigate them.

In Germany, we don't have a uniform structure that recruits people," a German counter-terrorism official told the paper.

Other Europeans including French, Swedish and Belgian citizens were reportedly also experiencing being recruited, as well as a "small, but growing number" of Americans.

Several videos threatening terrorist attacks were released in Germany ahead of last month's general election. One video spoke of retaliation for Germany's military presence in Afghanistan.

The number of western recruits to Islamist training camps in Pakistan and Afghanistan has reportedly increased in recent months, despite attempts by the CIA to aim drones at Taliban and al- Qaida operatives.(dpa)