ISLAMABAD - Two large anti-government marches entered the federal capital late Friday night, presenting the 15-month-old PML-N government with its biggest challenge yet.

Cricketer-turned-politician Imran Khan, who is leading his PTI’s Azadi March, says the May 2013 general election that brought Prime Minister Nawaz Sharif to power in a landslide was rigged, and has demanded he resign and hold new polls.

Populist cleric Tahirul Qadri is leading his own Inqilab March and he also wants to force the Sharif government to step down. Both Khan and Qadri plan to rally in Islamabad until their demands for Sharif's resignation and for electoral reforms are met.

The demonstration in Islamabad is the culmination of the "long marches" – in reality motorised cavalcades – which set off Thursday from the eastern city of Lahore, around 300 kilometres away. The marchers took more than 36 hours to reach the capital as convoys made stopovers in various cities along the road where they were warmly welcomed.

Police and witnesses said earlier on Friday that activists from Khan's Pakistan Tehreek-e-Insaaf (PTI) party clashed with supporters of Sharif's Pakistan Muslim League-N (PML-N) in Gujranwala, resulting in injuries to around a dozen people from the two sides. A stone-throwing mob attacked Khan's convoy as he led supporters through the city. Men brandishing ruling-party posters attacked his convoy, throwing shoes and stones.

Khan said shots were fired on his march, telling a television channel: "They threw stones at us...They fired bullets at us." However, police said there were no shots. Reportedly, a group of up to 40 youths who were following the convoy and shouting slogans clashed with workers from Khan's party before being dispersed by police.

In Islamabad, the loyalists of Dr Tahirul Qadri seemed to be in a mood to make the capital hostage again as his first battalion that reached Zero Point on Friday evening to welcome their leader were determined to follow the orders of their spiritual leader. The Inqlab March participants believed that they might be staying in capital for several days and were unsure about the expected gains.

Their informal partner, Pakistan Tehreek e Insaf, which had branded its rally as Azadi March, seemed not in a position to sustain for long in the capital. Their leader, Imran Khan, was reported missing in the midnight for quite some time. PTI activists kept waiting for him anxiously at Serena Chowk, where Khan reached after 2:30am.

The early birds among Dr Qadri’s followers, around 500-600 people and majority of them underage persons, reached Zero Point Islamabad in Friday evening and started waiting for their leader who was coming along with thousands of supporters could not reach there till 1 am on Saturday. Qadri at the last moment changed the rendezvous location to Aabpara Chowk, Suharwardi Road.

But Qadri’s supporters seemed to be a bit confused and their confidence level was not the same as was in the last year. For Example when Deputy Information Secretary of Pakistan Awami Tehreek (PAT) Umar Riaz Abbasi was asked that what they were going to extract from this Inqlab March, he said, "We cannot say anything yet but it depends upon the gathering and the situation that would unfold ".

However, he said they will remain non-violent and not try to make their demands accepted by the government by using force. And what they will get out of the March by following the rules and regulations was too early to be told. Abbasi also said that authorities did not erect any obstacle in their way to reach Zero Point and there was nothing to blame them about in that regard.

The marchers of Imran Khan's Azadi March who came from Khyber Pakhtunkhwa were found even more confused and aggrieved at the end of the day. Many of them were found saying that they were even not offered tea upon reaching here. They also seemed more tired.

The government, which opened all the entry points of the city, largely looked like a silent spectator in the whole scenario. It also accepted the demands of both rallying groups about the change of venues without much resistance. Certain quarters believed the government was taking time for assessing the eventual turnout of the two protests to set its further policy accordingly. Some observers said the size of rallies entering Islamabad, especially the PTI’s, was not as big as was expected.

As the security agencies have already hinted at possible militant activity during these political shows, the district administration on the instructions of the interior ministry intensified security. Though barriers and containers have been removed from the entry points of the capital, police are still there for security proposes. But no proper sanitation arrangements have been made for the thousands of marchers partly because of change of venues at the eleventh hour. However, the marchers had no problem in getting food as many makeshift shops were set up.

"Mian Nawaz Sharif, keep your resignation ready", Imran Khan tweeted as soon as his marchers reached federal capital's Serena Chowk. He declared that they will sit in the federal capital until prime minister resigns. "I will not leave (Islamabad) until Nawaz Sharif leaves his office." He said he was fighting to free the country from the clutches of this monarch. In another tweet, he said, "I will sleep among PTI workers tonight... We are fighting against the Gullu Butt system and we will defeat.”

Some members of Sharif's party have suggested the protests are secretly backed by elements in the military, which has had an uneasy relationship with Sharif. To what extent Khan and Qadri can destabilise the government is likely to depend on the stance taken by the armed forces, which has a long history of mounting coups. Few people fear a coup, but many officials think the threat of unrest will increase the military's hold over the government.

Both protest leaders command intense personal loyalty from their followers. Khan is a famed former international cricketer, known for his charity work, who now heads the third- largest legislative bloc in the country. He is protesting alleged irregularities in last year's voting. Qadri, a cleric and political activist who usually lives in Canada, controls a network of schools and Islamic charities. His followers intend to occupy Jinnah Avenue, Islamabad's main thoroughfare.