Lined up behind a black banner with the names of slain power workers, protesters on Thursday demanded an end to attacks against power stations and pipelines - part of the two-year armed campaign to undermine the US-led troops and the interim government.
Also on Thursday, in the southern city of Basra, more than 200 workers gathered outside a local government building to insist that the new government's ministers of oil and transportation be from their region.
"Everyone must know that the oppressed and persecuted people of the south refuse to have their interests be ignored," protesters said in a statement given to the provincial governor, Muhammad al-Wali.
Al-Wali agreed, saying: "We are eager that the people of Basra and the south have clout in the new government."
Some workers threatened to walk out. "We will stop pumping the oil and go on strike for those working in the oil field and the ports if our demands aren't met," Muhammad Abd al-Hafiz, an oil workers' union official and one of the protest's organisers, said.
Tensions and possible outages in Iraq, one of the world's key oil producers, have contributed to rising crude prices in the past year.
Security forces are perpetually
on alert outside power stations
The protests came as negotiators hammered out details of a new government that US officials hope will pave the way for an eventual withdrawal of coalition forces.
Jawad al-Maliki, a negotiator from the Shia-led United Iraqi Alliance, said Shia Muslim and ethnic Kurdish officials agreed to hold parliament's second-ever session early next week, although no date has been set.
The 275-seat National Assembly has held only one session - on March 16 - to swear in its members.
"The negotiations were positive and very good," al-Maliki said of Thursday's discussions. "In the coming days, the meetings will be continuous and decisive."
A Shia negotiator, Abdul-Karim al-Anzi, said lawmakers are expected to name the country's new president, two vice presidents, and parliament's speaker in their upcoming session.
One of the vice presidents will likely be a Sunni Arab, al-Maliki and al-Anzi both said.
UN envoy Ashraf Qazi (L) wants
fair representation for Sunnis
The move is an effort to reach out to the Sunnis, largely thought to be behind the country's armed resistance.
Kurdish leader Jalal Talabani is expected to be named president, with Shia politician Ibrahim al-Jaafari likely to become prime minister.
The top UN envoy in Iraq, Ashraf Qazi, reached out to Iraq's Sunnis on Thursday by meeting with influential Sunni religious leaders at a Baghdad mosque.
Qazi "stressed the importance of ensuring that all components of Iraqi society are adequately represented in the constitutional making process", a UN statement said.
A seven-member US congressional delegation also visited Iraq and expressed optimism at the progress being made in
forming a new government.