"We would like to advise our government, our congressmen, that there is something big going on and people do not understand it," he said. "You have many mosques around the United States...So the most dangerous things are going on in these mosques that have self appointed leaders throughout the United States. The extremist ideology makes them very active. We can say that they took over 80 per cent of the mosques in the United States...This means that the ideology of extremism has been spread to the youth and the new generation." Source
The Mapping Sharia Project sent trained people into mosques in the U.S. to find out how many of them are calling for jihad against America. They discovered that the majority of the mosques they've investigated so far do, in fact, promote jihad against America, in the Friday "sermons" (known as "khutbah") and in the literature available at the mosques.
In a speech by Mark Steyn, he said (when answering a question) Canadian Mounties did a survey of Canadian imams. It found 85 percent of the imams in Canadian mosques were "hardcore radical jihadists."
Saudi Arabia's oil wealth enables it to control around 90% of the world's Islamic institutions (source), and the Saudis promote hardcore, fundamentalist Islam. They pay for these mosques because it gives them control over what is taught and promoted at the mosques. Read more about this.
Authorities in Hamburg, Germany announced that they had finally shut down the Taiba mosque, which as the Al-Quds mosque in 2001 was a meeting place for several of the 9/11 jihad terrorists.
The Hamburg mosque was not singular. In recent years mosques have been used to preach hatred; to spread exhortations to terrorist activity; to house a bomb factory; to store weapons; to disseminate messages from bin Laden; to demand (in the United States) that non-Muslims conform to Islamic dietary restrictions; to fire on American troops; to fire upon Indian troops; to train jihadists; and much more.
The record of mosques in the United States is not much better. As long ago as January 1999, the Naqshbandi Sufi leader Sheikh Muhammad Hisham Kabbani declared in a State Department Open Forum that Islamic supremacists controlled most mosques in America: “The most dangerous thing that is going on now in these mosques,” he said, “that has been sent upon these mosques around the United States – like churches they were established by different organizations and that is ok – but the problem with our communities is the extremist ideology. Because they are very active they took over the mosques; and we can say that they took over more than 80% of the mosques that have been established in the US. And there are more than 3000 mosques in the US. So it means that the methodology or ideology of extremist has been spread to 80% of the Muslim population, but not all of them agree with it.”
Terrorism expert Yehudit Barsky affirmed the same thing in 2005, saying that 80% of the mosques in this country “have been radicalized by Saudi money and influence.” The Center for Religious Freedom found in 2005 a massive distribution of hateful jihadist and Islamic supremacist material in mosques in this country. And in June 2008 federal investigators found that the Islamic Saudi Academy in Virginia, despite promises to stop teaching such material, was still using books that advocated that apostates from Islam be executed and that it was permissible for Muslims to kill and seize the property of “polytheists."