Nitish Kumar's dream project - construction of the Ganga Driveway in Patna - is under threat.

Navayuga Engineering Company Limited, which is constructing the driveway, has written a letter to the state government on January 4, informing it that extortionists had issued a threat to the firm, demanding money.

The company has allegedly received threatening phone calls. It has stopped night shifts at the site, fearing attacks.

The project has already been delayed by more than a year and this new development will be another setback for the 23.5km-long project.

Bihar State Road Development Corporation Limited (BSRDCL), a wing of the road construction department, had awarded the construction work to the Hyderabad firm. The BSRDCL received a letter from Navayuga two days back. The construction company had also sent the copy of the letter to the Patna police.

BSRDCL official and deputy general manager of the project Sanjay Kumarsaid: "We received a letter from the construction company on January 4, through which they informed that they were getting threat calls."

Deputy chief minister and road construction minister Tejaswi sounded tough on the issue. "I will camp at the site to oversee the work being done, in case the threat is genuine. But if it is found that the construction company is trying to justify the delay in the execution of the projects citing fake threats, strong action will be taken against them," Tejaswi told The Telegraph over phone from New Delhi before boarding a flight to Patna.

Tejaswi had visited the site on December 11, 2015, to inspect the work pace. He had directed the executing agency to expedite the work as the project was already lacking pace. He had convened a meeting with the district magistrates of Patna, Saran and Vaishali in connection with the hurdles in land acquisition.

After the killing of the two engineers working for a private construction company in Darbhanga, allegedly by henchmen of the jailed gangster Santosh Jha, incidents of threat and extortion has increased in state.

The construction company quoted the Darbhanga incident as an example.

An assistant engineer in the construction firm, Harish, said: "After the incident in Darbhanga, we are all scared. Work is getting hampered as we are unable to work at night."

The police have also sprung into action.

"I have directed Patna senior superintendent of police Manu Maharaaj to deploy his forces at the construction site with immediate effect. It is not specific to this case only but wherever developmental work is on, under my jurisdiction. We will take up threats of extortion as top priority according to the instruction," said Shalin, deputy inspector-general of police.

Chief minister Nitish Kumar had laid the foundation stone for the Rs 3,160-crore-project at Digha Ghat (near the rail-cum-roadbridge) on October 11, 2013.

After the completion of the project, the travel time between Digha Ghat and Didarganj will be reduced from 2 hours to 20 minutes. It will also ease the traffic on the roads of Patna.