Nepal's Prime Minister Baburam Bhattarai was greeted with black flags by Maoist colleagues on his return home on Sunday evening from his maiden four-day India visit.
Nearly 100 hardliners of Unified Communist Party of Nepal (Maoist) owing allegiance to Vice-Chairman Mohan Vaidya shouted slogans and waved flags outside the Tribhuwan International Airport.
Bhattarai's colleagues were angry at him for signing what they term an "anti-national" Bilateral Investment Promotion and Protection Agreement with the southern neighbour.
The PM however has been insisting that despite fears of a backlash, he took the gamble of signing the agreement as it would attract huge Indian investment and help Nepal's development.
Addressing newspersons on his arrival, Bhattarai termed the visit as highly successful and stated that those protesting against BIPPA had failed to understand the terms of the agreement.
A large posse of security personnel was posted at the airport and along the route to Bhattarai's official residence in Baluwatar in anticipation of any untoward incident.
Terming the BIPPA as violation of party-discipline, Maoist general secretary Ram Bahadur Thapa said that the party could initiate disciplinary action against Bhattarai.
"The party standing committee meeting held a day before Bhattarai's departure for India had decided against signed the agreement. But the PM went ahead and signed it," Thapa told newspersons in Chitwan on Sunday.
Provisions in BIPPA provides grant of compensation by the host country to investors whose investments suffer losses due to war, armed conflict, national emergency, insurrection or riots.
India had been insisting on signing the BIPPA with Nepal as several major Indian investments had suffered huge losses. The present agreement will remain in force for 10 years.