India’s Kingfisher Airlines Tuesday declared a partial lockout till Thursday following instances of labor unrest and strikes in the company while the Aviation Ministry warned the crisis-laden air carrier that it would not be allowed to fly if safety norms were flouted.

In a statement, the debt-laden private air carrier controlled by liquor baron Vijay Mallya said: “Following a series of protracted and unabated incidents of violence, criminal intimidation, assault, wrongful restraint and other illegal acts including refraining from attending work, by a small section of recalcitrant employees which were all unnecessary and unprovoked, the management has been forced to declare a partial lock-out at the airline, effective immediately.”

The airlines said that though it had sufficient number of staff to operate its current schedule of flights as per the holding plan and a vast majority of the staff were willing to cooperate, they were not allowed to report to work on account of criminal intimidation by some of the recalcitrant employees.

Kingfisher cancelled all its flights Monday as a section of its workers refused to report to work over the non-payment of salaries.  The airlines had accused a section of the striking employees of intimidating and manhandling the other staffers on duty, stalling the operations.

In another development, Aviation Minister Ajit Singh warned the airlines that no Kingfisher flights would be allowed to operate till they cleared the mandatory safety norms and were certified by the engineers, IBN Live reported.

Asserting that passenger safety was the paramount concern, Singh warned that the cash-strapped airlines could be shut down if the safety norms were flouted.

The air carrier with a debt burden of about Rs 90 billion is operating under a contingency plan and running a few schedules. The carrier, named after Mallya’s flagship beer brand Kingfisher, had not paid salaries and credit dues to its staff since February. The beleaguered airlines recently announced that it had made part payment of salary dues to its employees.

Kingfisher Airlines has a total debt burden of over $1.4 billion and has not posted any profit since its inception in 2005. The company owes about $600 million to creditors, lenders, suppliers and employees in salary dues and operating expenses.