by Xu Haijing, Zhao Bo

CANBERRA, Aug. 25 (Xinhua) -- Four Chinese students are believed to have been injured in the attack earlier on Friday at the Australian National university campus in Canberra, in which an 18-year-old student assaulted a classroom of students with a baseball bat.

The attacker, who is a student at the university, took a baseball bat into a tutorial and began to hit other students and the female lecturer, who is also a student of the university taking a tutorial assistant role.

The four injured were sent to Canberra Hospital for treatment and two have been released by Friday evening.

A female student, who suffered from fractured front arm bone, had to stay overnight in the hospital for an operation the next day. She told Xinhua that the attack was unprovoked.

"He (the attacker) just stood up and started to bash the baseball bat to students sitting closest to him. Shouting something loudly, he randomly wielded the bat when walking towards the tutor."

"I was sitting close to the door but I don't have time to swipe my card to open the door. Beside the door is very heavy. Then he attacked me on my arm and it really hurts a lot," the girl, who did not want to be named, told Xinhua.

The girl, majoring commerce, said most students in the 20 plus class are Chinese students of the School of Commerce. As the new semester just started three weeks ago, students are not familiar with each other.

"I really don't know this guy (the attacker)," she said.

A male student staying overnight in the hospital suffered a fractured finger bone and slightly caved in skull. He said he was sitting behind the attacked and was hit when he was scratching his head and then hurt his finger.

Both students said some fellow students managed to tackle the attacker after the first moments of astonishment.

Diplomats from the Chinese embassy in Canberra visited the injured students in the hospital after meeting the university authorities to learn details of the incident.

The embassy published on its website warnings to fellow Chinese nationals in Australia to be alerted and keep safe.

According to Australian Capital Territory (ACT) Police, the 18-year-old offender was not known to police or intelligence agencies, while "lone wolf" terrorism has been ruled out as a motive.

"Shortly after 9:00 a.m., a man allegedly assaulted students and a lecturer with a baseball bat," ACT police said in a statement on Friday.

"During the class, the student stood from his seat with a baseball bat and approached the lecturer at the front of the class. Other students in the class intervened and attempted to restrain the student.

"Police took the 18-year-old man into custody and there is no known ongoing threat to public safety. At this early stage in the investigation it is too early to determine the motivation behind the assaults."

Meanwhile, ANU Acting Vice-Chancellor Margaret Harding moved to reassure students and families that there was no longer a threat to safety and security on the Canberra-based campus.

"I want to thank ANU Security and the ACT Police for their extraordinarily fast response to containing this isolated incident," Harding said in a statement.

"I also want to thank our students and staff who responded with extraordinary bravery.

"This event is shocking and unusual to our community. Canberra and ANU are caring communities where we pride ourselves on taking care of each other."

According to reports on the social media, ANU staff have offered counselling to those caught up in the incident.