Thousands of farmers in tractor convoys burst through police barricades Tuesday to take their protest against agriculture reform to the heart of India's capital, just as the nation marked Republic Day with a giant military parade.
Police had earlier sealed most entrances to the city with containers and trucks, but had to use tear gas and batons as the farmers broke through.
Some protesters reached a major intersection three kilometres (1.8 miles) from where Prime Minister Narendra Modi and other government leaders watched tanks and troops parade past and fighter jets fly overhead.
Modi waved to crowds and was driven back to his residence before any personal confrontation with the farmers, the biggest challenge his Hindu nationalist government has faced in its six years in power.
Tens of thousands of farmers have camped on the outskirts of the capital since November, protesting against new laws which deregulate produce markets.
Union leaders say the laws will allow private Indian conglomerates to take over the agriculture industry -- the rockbed of the economy -- and replace a system of purchases by the government at guaranteed prices.
Authorities had agreed to let the farmers stage a tractor rally as long as they waited for the official Republic Day parade to finish.
But flag-waving protesters on at least four major arteries climbed over or just pushed aside the barricades and concrete blocks and pressed on into the city.
"We are going to show the government that we mean business," said protester Nareesh Singh as he revved up his tractor and drove into a cloud of tear gas.
Satnam Singh Pannu, head of one of the main farmer committees, said the protesters have enough supplies to keep their Delhi camps going for a year if necessary, and that there was "massive popular support" for the campaign.
On one road, people on rooftops and threw petals on the tractor convoys.
Elsewhere people cheered and applauded as the farmers went past waving Indian flags and blowing horns.
The Republic Day ceremonies went ahead despite security concerns.
Police manned barricades at intersections around the centre of the city while soldiers with machine guns patrolled on many metro trains.
The parade -- which featured Rafale jets newly bought from France -- was cut back this year because of the coronavirus pandemic, with the number of spectators on the Rajpath boulevard reduced from 125,000 to 25,000.
Modi sent out Twitter greetings for the national holiday without mentioning the farmers.
The government says the reforms will boost rural incomes and say the farmers have been manipulated by opposition parties.
Ten rounds of talks between farm unions and ministers have failed to break the deadlock.
The farmers have demanded the government repeal the laws, but the administration has only offered to delay implementation for 18 months.
Smaller farmer demonstrations were held in Mumbai and Bangalore.
Farmers leaders said a new mass rally would be held on February 1 when the government announces its annual budget plans.
The occasion marks the day the constitution of India came into effect in 1950.