At least 13 anti-government protesters were killed Sunday by Iraqi security forces in one of the “worst” days of violence in the country's south amid widespread ongoing demonstrations against corruption, officials said.

Since the anti-government protests broke out in early October, at least 342 people have been killed and thousands more wounded in Baghdad and various southern provinces.

Demonstrators have taken to the streets by the tens of thousands over what they’ve called widespread corruption, a lack of job opportunities and poor basic services, despite the country’s oil wealth.

Protesters reacting to tear gas fired by riot police during fighting in Baghdad on Sunday. (AP Photo/Khalid Mohammed)

IRAQI PROTESTORS BLOCK MAJOR PORT, HALT COMMERCIAL ACTIVITY AMID ONGOING DEMONSTRATIONS

Seven protesters were killed Sunday in the southern province of Basra, near the main Gulf commercial port Umm Qasr, when Iraqi authorities used live fire and tear gas to diffuse the situation, according to security and hospital officials who did not want to be identified.

Four protesters reportedly were killed in Nassiriya province, and one killed in both Najaf, the seat of Iraq's Shiite religious authority, and Diwanieh provinces.

At least 150 demonstrators were injured across Southern Iraq.

Protesters had cut roads leading to the Umm Qasr port, halting all trade activity.

In Nassiriya on Sunday, protesters used burning tires to block key roads and main bridges. Protestors set fire to the city's Shiite Endowment building, a governing body regulating the administration of mosques.

Demonstrators trying to pull down concrete walls placed by Iraqi security forces to close in the historic Rasheed Street in Baghdad on Sunday. (AP Photo/Khalid Mohammed)

ROCKETS FIRED ON IRAQ BASE WITH U.S. TROOPS, NO ONE INJURED, PENTAGON SAYS

In Baghdad, at least 13 people were injured as clashes between anti-government protesters and security forces continued for a fourth day.

In the capital city, at least 16 people have been killed and over 100 injured in the renewed clashes, which kicked off last Thursday as protesters tried to scale a concrete barrier on historic Rasheed Street causing security forces to fire live ammunition, tear gas and rubber bullets to repel protestors.

The leaderless uprising has aimed to demolish the sectarian system and unseat the government, including Prime Minister Adil Abdul-Mahdi.

In statements, the international community, including the United Nations and the United States, denounced the use of force against peaceful protestors.

Secretary of State Mike Pompeo said last week that the U.S. would hit Iraq with new financial penalties to punish the tactics used to repel demonstrators.

An anti-government protester flashing a victory sign in Baghdad on Sunday. (AP Photo/Khalid Mohammed)

“We will not stand idle while the corrupt officials make the Iraqi people suffer,” Pompeo told reporters in Washington, adding that the U.S. “will use our legal authorities to sanction corrupt individuals that are stealing Iraqis' wealth and those killing and wounding peaceful protesters.”

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There was no indication that the protest movement has affected the production of oil, which has accounted for nearly 90 percent of Iraq's state revenue through exports.

Fox News’ Bradford Betz and The Associated Press contributed to this report.