Shady websites calling for a boycott of Qatar, a New York City billboard targeting the Gulf state's rulers, and a Vietnamese outfit floating hundreds of slander-ridden Facebook ads — all elements of a sprawling influence operation vilifying the country as it mediates between Israel and Hamas.

The murky operation, which began late last year and spans multiple countries, is the largest ever to target the wealthy emirate, disinformation researchers say, as the nine-month war between Israel and the Palestinian militant group rages on.

The campaigns, many using Islamophobic and anti-immigrant tropes, involve an anti-Qatar ad that featured at a U.S. gathering of political conservatives attended by Donald Trump and an online petition attributed to a fictitious person and organization.