Protesting farmers clashed with police at several places in the national capital and entered the iconic Red Fort and ITO in the heart of the national capital, with hundreds of them deviating from pre-decided routes, prompting security personnel to resort to lathi-charge and tear gas.

Pushed back by the police from the ITO in Central Delhi a section of the protesting farmers drove their tractors to Red Fort complex.

Chaos reigned for nearly 90 minutes as some protesters, including 'Nihangs' (traditional Sikh warriors), forced their way into the Red Fort and hoisted a flag from the staff from which the prime minister unfurls the tricolour on Independence Day.

Later, Delhi police were able to remove the troublemaking farmers from Red Fort premises where they had barged in.

Earlier, a clash broke out between police and protesting farmers after the latter reached ITO and tried to push towards Lutyen's Delhi, prompting the force to resort to lathi-charge and use tear gas shells against them.

Chaotic scenes were witnessed at ITO, where hundreds of protesters could be seen chasing police personnel with sticks and ramming their tractors into the buses parked by police.

At the ITO, a bus was vandalised by angry farmers.

Police on Tuesday fired tear gas shells and lathi-charged farmers when they clashed with the force in parts of city.

Police used tear gas on groups of farmers and resorted to baton charge as protestors broke past barricades with tractors at different border points and did not take the pre-decided routes for their march in the national capital.

The Delhi Police had given permission to farmers protesting the three farm laws to hold their tractor parade on selected routes only after the official Republic Day parade on the Rajpath concludes.

However, chaos ensued as the farmers were adamant on heading towards central Delhi.

In the morning, groups of protesting farmers camping at Singhu and Tikri border points of the national capital broke police barricades to force their way into the city.

The ITO resembled a war zone as restive crowds of farmers and uniformed security personnel could be seen in the area. Police fired tear gas shells at hundreds of farmers who wielded sticks and clubs and entered ITO, a few kilometres away from Parliament, in an effort to move towards Rajpath.

Police baton-charged farmers at Chintamani Chowk in Shahdara when they broke barricades and smashed windowpanes of cars. A group of 'Nihangs' (traditional Sikh warriors) clashed with security personnel near Akshardham Temple.

At Nangloi Chowk in west Delhi and at Mukarba Chowk farmers broke cemented barricades and police used tear gas to disperse them.

An official said police personnel used tear gas to disperse groups of farmers coming from the Singhu border point as they tried to hold a march on the Outer Ring Road much ahead of the allotted time.

Meanwhile, senior farmer Balbir Singh Rajewal said farmers were following the pre-decided route. No one from the Sankyukt Kisan Morcha went to the Outer Ring Road.

"We condemn violence against farmers, appeal to all to maintain peace," Rajewal told PTI.

The Delhi Police appealed to the protesting farmers to not take law in their hands and maintain peace as clashes between the force and protesting farmers broke out at a number of places in the national capital.

The police also asked the farmers to head back to their pre-decided routes for the tractor parade.

"We request to the protesting farmers to not take law in their hands and maintain peace," Additional PRO Anil Mittal said.

A member of the Sankyukt Kisan Morcha, an umbrella body of 41 unions, leading the protest against the three central farm laws at several border points of Delhi, said those who broke the barricades at Tikri border points belonged to the Kisan Mazdoor Sangharsh Committee.

He said the Sankyukt Kisan Morcha's tractor parade will start as scheduled after police give farmers way. The Kisan Mazdoor Sangharsh Committee on Monday announced that they would hold their march on Delhi's busy Outer Ring Road on Republic Day.

The entry and exit gates of more than 10 metro stations in central and north Delhi were temporarily closed on Tuesday following clashes between police and protesting farmers in part of the national capital.

The Delhi Metro Rail Corporation took to Twitter to inform the public about the temporary closure of metro station gates.

"Entry/exit gates of Indraprastha metro station are closed. Entry/exit gates of Samaypur Badli, Rohini Sector 18/19, Haiderpur Badli Mor, Jahangir Puri, Adarsh Nagar, Azadpur, Model Town, GTB Nagar, Vishwavidyalaya, Vidhan Sabha and Civil Lines are closed," the DMRC tweeted.

Earlier in the day, chanting 'rang de basanti' and 'jai jawan jai kisan' numerous farmers rode tractors, motorbikes, horses and even cranes to cross the national capital's borders into the city for their proposed parade against the three contentious farm laws.

Locals stood on both sides of the roads at various locations showering flower petals on the farmers amid drum beats.

Standing atop vehicles decked up with flags, the protesters danced to the tune of patriotic songs such as 'Aisa desh hai mera' and 'Sare jahan se achcha'.

Thousands of farmers, mostly from Punjab, Haryana and western Uttar Pradesh, have been camping at several Delhi border points since November 28, demanding a complete repeal of three farm laws and a legal guarantee on minimum support price for their crops.