GAZA, March 18 (Reuters) - A previously unknown group in the Gaza Strip calling itself Ansar al-Sunna (Followers of the Sunnis) send out an SMS message to media claiming to have fired a rocket that killed a man in Israel on Thursday.

The name, which is also used by al Qaeda allies in Iraq and elsewhere, indicated that the group belongs to hardline Salafist tendencies in the Palestinian enclave which have challenged the ruling Hamas Islamist movement. Hamas has been trying to enforce an informal ceasefire between Israel and the territory.