One man was stabbed and suffered a broken pelvis and another was bitten by a dog in an attack onboard a Sheffield bus.
Violence erupted on the X30 Handsworth service operated by TM Travel as it travelled out of Sheffield towards the Parkway.
South Yorkshire Police said a man and woman, who had a brown Staffordshire bull terrier with them, boarded the bus in Arundel Gate in the city centre and attacked two men, aged 63 and 55.
The 63-year-old suffered a broken pelvis and stab wound to his arm and the 55-year-old man suffered a cut to his neck and dog bite to his arm.
Their attackers jumped off the bus and ran across the Parkway towards Park Hill.
A police probe into the incident is underway, with officers describing the attack as 'unprovoked'.
CCTV footage has been examined and witnesses have been interviewed but the culprits, who were both in their early 20s, have not yet been traced.
A South Yorkshire Police spokeswoman said: “This incident appears to have been unprovoked and resulted in both men receiving nasty injuries.
“We have carried out extensive enquiries, including reviewing CCTV and interviewing potential witnesses, however this has not led us to a positive identification of the suspects.
“It happened on the night that England played Wales in the Euros and we are appealing for any witnesses to come forward.
“Were you on the X30 bus that night or did you see or hear anything suspicious?"
Anyone with information should call South Yorkshire Police on 101.