Facebook on Wednesday banned ads on its flagship website and Instagram that claim widespread voting fraud, suggest US election results would be invalid, or which attack any method of voting.
The company announced the new rules in a blog post, adding to earlier restrictions on premature claims of election victory.
The move came a day after US President Donald Trump used the first televised debate with Democratic challenger Joe Biden to amplify his baseless claims that the November 3 presidential election will be "rigged".
Trump has been especially critical of mail-in ballots, and he cited a number of small unrelated incidents to argue that fraud was already happening at scale.
Facebook has been under fire for refusing to fact-check political ads more broadly and for rampant organic misinformation.
Citing hate speech rules, it also moved Wednesday to remove Trump campaign ads suggesting that immigrants could be a significant source of coronavirus infections.
Facebook said the new election ad prohibition would include those that "portray voting or census participation as useless/meaningless" or that "delegitimize any lawful method or process of voting or voting tabulation... as illegal, inherently fraudulent or corrupt".
A Palestinian teen has been shot dead during an Israeli military raid in the occupied West Bank on Wednesday, the official Palestinian news agency Wafa reported.
Some 287 candidates will be considered for the 2026 Nobel Peace Prize, the secretary of the Norwegian Nobel Committee said on Thursday, with US President Donald Trump likely to be among the nominees.
At least 17 migrants have died, and nine are missing after their boat broke down and drifted for eight days in the Mediterranean Sea, Libya's Red Crescent and Libyan security sources said on Wednesday.
Israel has begun taking control of aid ships bound for Gaza far from Israeli shores, Israeli army radio cited an Israeli source as saying on Wednesday.
Donald Trump discussed how to mitigate the impact of a possible months-long US blockade of Iran's ports with US oil companies, a White House official said on Wednesday, as the US president urged Tehran to 'get smart soon' and sign a deal.