The opposition in both houses of Parliament on Thursday raised the issue of lynching of a Muslim man in Rajasthan's Alwar district by cow vigilantes, with a Congress leader blaming an "organised gang" and the government promising justice.

Congress leader Mallikarjun Kharge raised the matter in the Lok Sabha, while his party colleague Madhusudan Mistry raised it in the Rajya Sabha.

Home Minister Rajnath Singh assured Lok Sabha members that the Centre will ensure justice in the case while Minister of State for Parliamentary Affairs Mukhtar Abbas Naqvi told the Rajya Sabha that a "message should not go out that the house is supporting cow slaughter".

Mistry said the self-styled 'gau rakshaks' were harassing and killing people in the name of cow protection.

"The cow vigilante gang acted as if they have some extraconstitutional powers. They checked trucks to see if there were cows or calves -- and if the owner was Hindu, they let them go," he said.

"It is being done by an organised gang. Such gangs are present in Madhya Pradesh and Gujarat; and now, they are in Uttar Pradesh. It is a complete breakdown of constitutional machinery in the state," Mistry said as he was supported by other opposition leaders.

Naqvi, however, said the incident did not occur as the Congress MP said.

"This is a sensitive issue. A message should not go (out) that this (upper) house is supporting cow slaughter. The incident did not occur as the member is narrating," Naqvi said.

Leader of Opposition in Rajya Sabha Ghulam Nabi Azad said: "I haven't come across such an insensitive government."

Deputy Chairman P.J. Kurien asked the government to submit a report to the house, so that the issue could be addressed.

In the Lok Sabha, however, the government did not deny the incident. The Home Minister rather assured of justice.

Kharge, who raised the issue, said: "It's not good to take law into (one's own) hands. It's a serious matter. This is the fifth incident in a row. Earlier, such cases were reported in Uttar Pradesh and Haryana also."

"This is not a stray incident... three such incidents have happened in Uttar Pradesh, two in Gujarat and two in Haryana," Kharge said.

The Home Minister said: "The state (Rajasthan) government has taken cognisance of the matter. An FIR has been registered and some arrests made. the Centre will try that justice prevails," Singh said.

Pehlu Khan, a Muslim man in his 50s, was brutally beaten up by cow vigilantes in Rajasthan's Alwar district on Saturday while transporting cows. Khan succumbed to his injuries on Monday night in a hospital.