It was the deadliest terror attack inside Iran in almost a decade.
The attack killed at least 25 people nearly half of them members of the country's elite Revolutionary Guards.
The massive ceremony started at 8:30 a.m.
The mourners, mostly wearing black, carried pictures of the dead along with banners reading "we will stand to the end" and "no to terrorism".
Two of the men spoke in Arabic about jihad, while the third spoke in Farsi suggesting they were targeting Iranian Revolutionary Guards, according to the recording, released after Saturday's assault on the Guards in the Iranian city of Ahvaz.
The political deputy governor of Khuzestan Province, Ali Hossein Hosseinzadeh, put the death toll from the attack at 25, saying 60 others have been injured.
Speaking before leaving Teheran to attend the annual UN General Assembly in New York, Mr Rouhani accused US-backed Gulf Arab states of providing financial and military support for anti-government ethnic Arab groups in Iran.
Reuters reported that Islamic State's Amaq agency posted a video that purportedly showed three men in a vehicle on their way to the parade.
'We are Muslims, they are kafirs (non-believers),' the man says.
Earlier in the day, Iran's intelligence minister Mahmoud Alavi told the media the security services uncovered a large network of suspects.
Nikki Haley, the USA ambassador to the United Nations, rejected Iran's accusations.
On June 7, 2017 in Tehran, 17 people were killed and dozens wounded in simultaneous attacks on the parliament and on the tomb of revolutionary leader Ayatollah Ruhollah Khomeini - the first inside Iran claimed by IS.
Any connection to the attack on the military parade was unclear.
Responding to Rohani's accusations, the US ambassador to the UN, Nikki Haley, told the BBC that Iran should "look in the mirror" for the causes of the attack, saying that Iran had "oppressed its people for a long time".
The New York Timesreported that Supreme Leader Ayatollah Ali Khamenei said of the attack: "The crime is a continuation of the conspiracy of USA -backed states in the region, which has set itself the goal of creating insecurity in our beloved country". "Therefore, your victory is indeed a victory for the [Iranian] nation and a defeat for the extended front of Iran's enemies", the Leader added.
U.S. Secretary of State Mike Pompeo, asked by a Fox News interviewer if the United States played any role in the attack, said: "When you have a security incident at home, blaming others is an enormous mistake".
The father of 4-year-old victim Mohammad Taha lay atop his son's flag-draped coffin sobbing, a public display of grief near the Sarallah Mosque in Ahvaz, the capital of Iran's oil-rich province of Khuzestan.
The "formal incitement against the UAE from within Iran is unfortunate, and has escalated after the Ahvaz attack", Minister of State for Foreign Affairs for the United Arab Emirates Anwar Gargash said.
Republicans, who hold a paper-thin majority in the Senate, can ill afford defections if Kavanaugh is to be approved. Kavanaugh , also due to testify at the Judiciary Committee hearing, has denied the accusations by Ford and Ramirez.
That equates to an increase of about 1 million bpd, but the latest data shows they are some way from achieving that target. The next meeting of the conference - the full group of OPEC and non-OPEC ministers, is not until December.
He was fantastic today, and picking up the side's first clean sheet of the season, fans can finally give him plenty of praise. But Lacazette ensured that lethargic spell wouldn't prove costly when he smashed a sublime opener in the second half.
A four-year veteran of the department, Guyger has the right to appeal the disciplinary action, according to the tweet. When she put her key in the apartment door, which was unlocked and slightly ajar, it opened, the affidavit said.
The Motorola One Power features a 16MP+5MP dual-rear camera setup, while at the front it features an 8MP selfie camera. The Motorola Power One is priced at INR 15,999 and will be available exclusively on Flipkart , starting October 5.
The rovers move by "hopping" up to 15 metres at a time because the extremely weak gravity on the asteroid makes rolling hard . Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate.
The motion comes after weeks of pressure from its overwhelmingly pro-EU membership and comes with some major caveats. Tottenham MP David Lammy and peer Lord Adonis were among the speakers while MP Luciana Berger led the march.
49ers Fear Jimmy Garoppolo Suffered Torn ACL Against Chiefs
In the split second before Garoppolo was blasted by Nelson, his knee left knee buckled, leaving him on the turf in obvious pain. The 49ers are 1-2 and crossing their fingers about their quarterback. 49ers: Play the Chargers in Los Angeles next Sunday.
Accuser of Trump's court nominee sets conditions for testifying
Grassley said the Senate Judiciary Committee has offered to hold a hearing with Ford in any format, time and place of her choice. He said he was "disturbed" to hear that she had been facing threats and harassment but urged her to speak before the committee.
Michael Kors to buy out Versace for at least $2B
Michael Kors and private equity firm Blackstone, which owns 20% of Versace, did not immediately respond to a request for comment. The 40-year-old fashion house returned to profit in 2017 and reported revenue of almost $800 million.
Amazon's latest Alexa devices draw praise from experts
Well, it retains Bluetooth as well as aux output, which apparently let you hook it up to a bigger speaker ( if you have one ). The other product spotted is the Amazon Smart Plug , which allows you to add Alexa voice control to any electrical socket.
Donald Trump hints he may 'get rid of' Rod Rosenstein
John McCain, who died away last month, for sinking the GOP health care bill, though he did not mention the late war hero by name. Bromwich, released statement saying his client did not leak the memos he made while at the Federal Bureau of Investigation .
Could you stay 30 hours in a coffin?
If you think you can spend 30 hours in a coffin, fill out the registration form and submit it before midnight, on October 3. Six Flags Saint Louis is challenging six people to spend 30 hours in a coffin in honor of its 30th year of Fright Fest.