Prime Minister Narendra Modi on Monday launched a scathing attack on the Congress on birth anniversary of B R Ambedkar, accusing the party of turning Scheduled Castes, Scheduled Tribes and OBCs into "second-class citizens" while in power.

Addressing a gathering after flagging off the first commercial flight from the Maharaja Agrasen airport here to Ayodhya and laying the foundation stone of a new terminal building at the airport, he alleged that the Congress has become the destroyer of the Constitution framed by Ambedkar."

Babasaheb Ambedkar wanted to bring equality, but Congress spread the virus of vote bank (politics) in the country. He wanted every poor person to live with dignity, with heads held high, to dream and fulfil them. But the Congress made the SCs, STs and OBCs second-class citizens," he said.

Sharpening his attack on the main opposition, Modi alleged the Congress turned the pious Constitution "into a weapon to gain power" and spread the "virus" of vote bank (politics).

During the years-long rule of the Congress, water reached the swimming pools of the party's leaders but tap water did not reach villages, he claimed. "Even 70 years after Independence, only 16 per cent of homes in villages had tap water... Who were the most affected by this? It was the SCs, STs and OBCs."

He slammed the Congress leadership, saying if they were so much concerned about the welfare of the downtrodden, those making speeches "on every street these days" should have ensured that water reached the homes of SCs, STs and OBCs when the party was in power.

Modi said, "We do not have to forget what they did with Ambedkar. The Congress insulted Babasaheb when he was alive and he was defeated in elections twice. The then Congress government wanted to throw him out."

"A conspiracy was hatched to keep him out of the system. When Ambedkar was no more, the Congress even tried to erase his memories. It wanted to finish even his ideas," he said.

After flagging off the flight from here to Ayodhya and laying the foundation stone of the new terminal building, Modi said the BJP-led government at the Centre was emphasising connectivity on one hand and on the other was ensuring social justice and welfare of the poor. "This was the dream of Dr Ambedkar," he stressed."

This is what our constitution makers and those who sacrificed their lives for this nation had aspired for our country. These were their dreams," Modi told the gathering.