premise: The Iraqiya channel quoted an Interior Ministry official as saying that the curfew began at 8:00 p.m. (1700 GMT) Thursday and all people and vehicles must stay off the streets of the city until further notice.
  In other violence, gunmen attacked a Shiite ministry in central Baghdad, prompting fierce clashes with security guards.
  "Up to 30 gunmen attacked the Health Ministry in Bab al-Mu' adham area at about 2:30 p.m. (1130 GMT), prompting fierce clashes with Iraqi army and police forces," an Interior Ministry source told Xinhua.
  "There is no immediate police report on casualties," the source said, adding that there were some people being taken to nearby hospitals.
  Deputy Minister Hakim al-Zamily told the Iraqi state-run television Iraqiya that since Thursday morning the ministry building has been shelled by mortar rounds and machine-gun fire.
   What would be more likely at night without the curfew that began on Thursday?
hypothesis: 30 gunmen attacked the Health Ministry