Iraqi authorities shoot dead two protesters as unrest continues
This was followed by reports of gunfire from behind concrete barricades where security forces were deployed, according to news agency, AFP.
The capital's historic Rasheed Street and its nearby colonnaded alleys where riot police have clashed with demonstrators has become a major flashpoint.
Young demonstrators donned helmets and medical masks to face off with security forces unleashing tear gas.
In southern Iraq, protesters sealed off streets with burning tyres as schools and public offices stayed shut a day after anti-government rallies descended into bloodshed.
For nearly two months, the capital and Shia-majority south have been gripped by the largest protests since the 2003 US-led invasion that toppled Saddam Hussein.
Demonstrators - most of them teenagers - throw rocks from behind their own makeshift barricades in daily skirmishes that have transformed the historic heart of Baghdad into a flashpoint.
The clashes left another 18 demonstrators wounded near al-Ahrar on Tuesday, according to a medical source.
Many of the young men had been there for days or weeks without going home, with one telling AFP: "We won't leave unless it's in coffins."
The street violence has left more than 350 people dead and around 15,000 wounded since the start of October.
Public anger over a lack of jobs fuelled the latest grassroots protests, Iraq's most widespread and deadly in decades.