BHUBANESWAR, India (Reuters) - Hundreds of indigenous people waved flags and shouted slogans in eastern India on Monday to protest against an order to evict more than one million indigenous families accused of encroaching on forest lands, witnesses said.

The Supreme Court issued a Feb. 13 order to remove forest dwellers in 21 states where about 1.3 million land claims, each potentially representing a household, were rejected.

The case highlights the plight of India’s underprivileged lower castes and indigenous groups as the world’s second most populated country - with 1.3 billion people - juggles with environmental protection, poverty reduction and economic growth.

Worried about conservation of forests, some environmental groups had filed the initial petition seeking evictions, and state governments had disputed the families’ land claims made under a forest rights law.

But Prime Minister Narendra Modi’s Bharatiya Janata Party (BJP) opposes the evictions, which the court ordered by mid-July.

On Monday, protesters marched to the city of Behrampur in Odisha state. Many waved placards, including one that said: “Stop eviction of tribal families and forest dwellers from their homeland.”

Bhalchandra Shadangi, a protest leader, told Reuters by phone that the court order was “an undeclared war on tribals” and nearly 150,000 people faced eviction in Odisha.

Activists say federal and state governments have for decades diluted land rights for indigenous people and bowed to pressure from mining companies in the mineral-rich central and eastern states of Odisha, Jharkhand and Chhattisgarh.

The three states are also home to a decades-old Maoist, or Naxalite, insurgency that fought security forces over land and mineral resources in indigenous forest areas, although their fight has waned in recent years.

In Chhattisgarh, where the main opposition party Congress recently came to power, the state government is considering an appeal against the Supreme Court order, Chief Minister Bhupesh Baghel said in a tweet on Monday.

The BJP party president Amit Shah said on Monday all states ruled by the party would soon file review petitions challenging the order and “care will be taken to safeguard the rights of our tribals and prevent eviction.”

Monday’s protests at Behrampur followed a march on Saturday by indigenous protesters in the state of Jharkhand, where more than 28,000 people face eviction, according to the order.

Birendra Kumar, an activist leader in Jharkhand, said a rally was planned for New Delhi on March 2. “The Supreme Court direction is wrong and it is anti-tribal,” he said.