A masked gang broke into a house and attacked a couple inside with a metal bar or hammer, police said.
A woman in her 30s suffered facial injuries and a man in his 40s suffered cuts to his head during the assault on Oxton Road in Birkenhead, Wirral.
Merseyside Police said the couple were treated in hospital after the men broke in around 03:50 BST on Monday.
Det Insp Sarah Wilkinson said: “This was a nasty assault on the couple and work is ongoing to establish any possible motive.”
