Several thousand Pakistanis poured onto the streets of Islamabad on Monday, chanting "death to America" and demanding holy war at a rally whipped up by right-wing, religious and banned organisations.
It was the latest show of support for Defence of Pakistan, a coalition of around 40 parties chaired by a cleric dubbed the father of the Taliban that include organisations blacklisted at home and abroad as terror groups.
"Today, we have gathered here to raise a voice of protest against US intervention in Pakistan," chairman Maulana Sami ul-Haq, who runs an extremist madrassa that educated several Taliban leaders, told AFP. Also present was member Hamid Gul, who headed Pakistan's Inter-Services Intelligence agency during the 1980s Pakistani-sponsored war against Soviet troops in Afghanistan that gave rise to al Qaeda and the Taliban.
His membership has helped fuel suspicions that Pakistan's security establishment is backing the coalition as a means of exerting pressure on the weak government and whipping up rhetoric against the unpopular US alliance.
"Our protest is against the possible resumption of NATO supplies, US and Indian occupation and to strengthen the country's defence," Haq told AFP.
"America wants to break Pakistan into pieces," he added in reference to a resolution sponsored by three US lawmakers calling for self-determination in Pakistan's insurgency-torn southwestern province of Baluchistan.
The alliance, which uses Twitter and Facebook to promote its message, was set up after US air strikes killed 24 Pakistani soldiers on the Afghan border in late November, which saw Pakistan shut its Afghan border to NATO supplies.
"Death to America" and "America deserves one treatment: jihad, jihad" shouted the crowd in a bustling commercial area, an AFP reporter said.
The coalition has already attracted large turnouts at a series of rallies across the country that some see as a build up to contesting Pakistan's next general election, which could be called within months.
Allah Buksh, a senior police official, said 2,500 attended the demonstration as it got underway, but witnesses estimated the crowd at 3,500 as hundreds of riot police, armed with batons and wearing bullet-proof jackets stood guard.
"America can never be our friend, it is our biggest enemy. America will be defeated in Afghanistan and divided into pieces," Mian Aslam, a former lawmaker from the religious Jamaat-e-Islami party told the rally.
Banners strung up in Islamabad denounced US drone strikes on Islamist militants, the government's decision to grant India most favoured nation status in a bid to ease trade, and re-opening the Afghan border to NATO convoys.
"Go America Go," "No to NATO," "Arrogant Americans - others are also human beings," and "the chains of slavery will now break up," they read.
"The friend of the US is a traitor," "the friend of (Pakistani President Asif Ali) Zardari is a traitor" and "the friend of (Afghan President Hamid) Karzai is traitor," shouted the crowd.
The government banned three key members of the alliance from attending, including Hafiz Saeed, who heads Jamaat-ud-Dawa, seen as a front for the Lashkar-e-Taiba militant group blamed for the 2008 Mumbai attacks.
Organisers said they would not challenge the ban. "We have installed 10,000 chairs for today's rally and expect a very successful show," Yahya Mujahid, a spokesman for JuD, told AFP.
"Hafiz Muhammad Saeed will not come to Islamabad to avoid confrontation with the government and will not attend the rally," Mujahid said.