The Council on American Islamic Relations (CAIR), a part of the U.S. Muslim Brotherhood, is organizing a letter-writing campaign joining the many global Muslim Brotherhood organizations attempting to organize protests against Israeli counter-terror actions in Gaza. According to a statement on the CAIR website:
The Council on American-Islamic Relations (CAIR) is calling on khateebs (speakers) to give time in their Friday khutbas (sermons) tomorrow toward the completion of a campaign to send 10,000 letters to members of Congress advocating an end to the illegal blockade in Gaza. CAIR volunteers will provide letters at mosques to be signed by individuals. CAIR will then send these letters to your representatives in Congress.
CAIR itself had its origins in the Hamas support infrastructure in the US. Numerous posts have already described the efforts of the global Muslim Brotherhood to support Hamas and organize protests against Israeli actions in Gaza.