"A group of 20-25 youths, shouting slogans hailing MNS, stormed the Indiabulls' office at Camp area around 12 PM and damaged the windowpanes and a glass door," a company spokesman told PTI.
He said some employees of the company present inside the office at the time of the attack, along with security guards, foiled the bid of the vandals to force their way inside.
An FIR has been registered with Gadgenagar police station in this connection, the spokesman said, adding no CCTV cameras are installed in the premises.
Police are recording the statements of the staff present in the office at the time of the attack.
Monday's was a second attack on an Indiabulls' establishment within 24 hours of MNS chief's call to launch an agitation against the company for "usurping" water to run its power plant at Nandgaonpeth.
Alleged MNS workers had damaged the glass entrance of the company's office in Central Mumbai last evening.
"I appeal to you all to launch an agitation against Indiabulls from Monday. The company has usurped water meant for farmers to get its power plant located at Nandgaonpeth near here functional," Thackeray had said addressing a party rally here yesterday.
Amravati is among several districts of Maharashtra reeling under severe drought.
Meanwhile, security at Indiabulls' office at its Sophia Power Plant, located in MIDC area near Nandgaonpeth, has been tightened.
The Bombay High Court had recently rejected an application by Vidarbha's farmers to recall its March 2 order wherein it had upheld allocation of 87.6 million cubic metres of water annually to Indiabulls' thermal power plant.