One bystander was killed and 130 people were injured on Friday as pro-reform protesters and government supporters clashed in Amman, prompting police to use water cannons to disperse them.
Government loyalists hurled large stones at demonstrators, injuring more than 100 protesters, Al Arabiya correspondent in Amman said.
Amer Khairy Saad told Reuters his father, Khairy, 57, died in hospital after police beat him as they were trying to disperse the opposing crowds who had gathered near the Interior Ministry in the Jordanian capital.
"My father left the house to make sure my brother was okay. And then he found police beating him, he was taken to hospital and he died there," the son, Amer, told Reuters.
What happened today is definitely the start of chaos and it is unacceptable and I warn of the consequences..I ask you, where are you taking Jordan? 
About 200 people attacked the sit-in, in which around 2,000 youths from different movements, including the powerful Islamist opposition, took part to call for reforms to the current regime and more efforts to fight corruption.
Despite the attack, the second of its kind in as many days, students remained at the demonstration next to the Interior Circle, or Gamal Abdul Nasser Square, in the capital.
Jordan's Prime Minister Marouf al-Bakhit said clashes between pro-monarchy and pro-reform protesters, was the beginning of chaos and warned of consequences if similar clashes occurred.
The prime minister also blamed opposition Islamist group for the clash, which left one person dead after police attempted to disperse the protest near the Interior Ministry.
"What happened today is definitely the start of chaos and it is unacceptable and I warn of the consequences," Bakhit told Jordanian television.
Addressing Islamists, he said: "I ask you, where are you taking Jordan?"
He said they were trying to "create chaos" and were getting orders from Egypt and Tunis.
Vowing to press
If they think that the attack will force us to go home, they are wrong. Attacks will only make us stronger and determined to stay here
Earlier on Friday, Jordanian students vowed to press on with their sit-in protest in central Amman to demand reforms after government supporters attacked them with stones on Thursday night, injuring at least 30 people.
"They are trying to push us to leave," Saddam Basrawi, a 21-year-old university student, told AFP.
"Last night, they attacked us with stones, but we will endure and we will not budge no matter what happens."
Around 500 youths from different movements, including the powerful Islamist opposition, had camped out in the rain and cold weather to call for reforms to the current regime and more efforts to fight corruption.
"Our gathering is peaceful, but this did not prevent the attacks. Does the king (Abdullah II) agree with such actions? We are Jordanians and we have the right to express ourselves," said Reda Darwish, 20.
"If they think that the attack will force us to go home, they are wrong. Attacks will only make us stronger and determined to stay here."
At nightfall on Thursday, police attempted to disperse the youths, cutting off electricity to the square around 11:00 pm (2100 GMT), an AFP journalist witnessed.
Loyalists attack
Jordan, your turn is coming
Protesters said around 50 "loyalists" attacked them with rocks after the power supply was lost, saying police who surrounded the scene did not intervene.
"We hold the interior minister responsible for this incident and we call on the king and the people to protect us from these thugs who are attacking us," said Nihad Zuhair, another protester.
Police spokesman Mohamad Khatib told AFP he was not aware of any casualties.
The protest camp came in response to a call on the social network site Facebook, a tool of many of the recent protests that have sprung up in Arab countries.
The students called for corrupt officials to be put on trial and demanded security services stop interfering in their affairs.
"The revolution is happening all around us," they shouted: "Jordan, your turn is coming."
"We want constitutional amendments to have parliamentary governments," said Alaa Fazaa of the Jayeen (We are Coming) group, adding the protests would go on until their demands were met.
Since January, left-wing activists have joined forces with nationalists and the Islamist opposition in calling for far-reaching political reforms and an end to what they say is rampant corruption.
The Islamist movement is planning a demonstration after Friday midday prayers to push for reforms and mark the 43rd anniversary of the Battle of Karameh with Israel.
The government has formed a national dialogue committee to speed up reforms, but the panel is facing problems after the Islamists and others refused to take part.