The leaders of Britain, France and Italy want tech companies to aim to remove postings that promote terrorism within just an hour or two after they appear.

British Prime Minister Theresa May said Wednesday companies are making progress but need to go "further and faster." She says the average lifetime of Islamic State extremists' online propaganda shrank from six days to 36 hours from January through June.

But, May says, "that is still 36 hours too long."

French President Emmanuel Macron and Italian Prime Minister Paolo Gentiloni joined May to convene world leaders and tech leaders to discuss the issue at the United Nations.

Internet services have come under increasing pressure to rid themselves of terrorist messages. Facebook, Microsoft, Twitter and Google-owned Youtube recently launched a joint