BAGHDAD (AP) — Iraq's Shiite religious establishment on Friday condemned attacks on peaceful protesters after a month of massive anti-government demonstrations in which security forces have killed at least 250 people.

Thousands of protesters continued to clash with security forces on two bridges leading from Baghdad's Tahrir Square to the heavily fortified Green Zone where the government is headquartered. At least 50 people were injured by tear gas and rubber bullets, according to security and medical officials who spoke on condition of anonymity because they were not authorized to talk to reporters.

Videos circulated online of a group of protesters smacking their shoes against a poster showing Iran's Supreme Leader Ayatollah Ali Khamenei and the head of its elite Quds force, Gen. Qassim Soleimani, with their faces crossed out. The video appeared to have been taken in Tahrir Square on Thursday. Many protesters have directed their rage at Iran, which has close ties to powerful political parties and state-backed militias.

This month's protests in Iraq and similar demonstrations in Lebanon are fueled by local grievances and mainly directed at political elites, but they also pose a challenge to Iran, which closely backs both governments. An increasingly violent crackdown in Iraq has raised fears of a backlash by Iran and its allies.

Ahmed al-Safi, delivering a Friday sermon on behalf of the country's top clerics, said that they condemn "attacks on peaceful protesters and all forms of unjustified violence," and that those responsible should be held accountable.

He also said authorities should not allow "any person or group or biased entity, or any regional or international party" to impose its view on the Iraqi people — an apparent reference to Iran.

The sermon was delivered in the Shiite holy city of Karbala, where masked men suspected of being linked to the security forces opened fire on protesters earlier this week, killing at least 18.

The protests are fueled by anger at widespread corruption, high unemployment and poor public services. The protesters have called for the resignation of the government and sweeping changes to the political system established after the 2003 U.S.-led invasion.

Iraq has held regular elections since then, but they have been dominated by sectarian political parties, many of which are close to Iran. The protests have erupted across Baghdad and mostly Shiite southern Iraq, and have been directed against the Shiite-led government. In southern Iraq, protesters have attacked and set fire to political party offices.

On Thursday, Iraqi President Barham Salih said he would approve early elections once a new electoral law is drafted, expressing support for the protesters but saying reforms would have to be enacted through constitutional means. He said Prime Minister Adel Abdul-Mahdi is willing to resign once political leaders agree on a replacement.

But the process of forming a new government could take weeks or even months, and a reshuffle of the Cabinet seems unlikely to satisfy the protesters.

Thousands of protesters gathered in the main square of Najaf, another Shiite holy city, late Thursday. Groups of men danced and waved Iraqi flags, while volunteers handed out falafel sandwiches cooked on site.

"This is a great revolution," said Marwa Ahmed, one of several women who joined the protest. "We will not give up or back down until our demands are met."

Krauss reported from Beirut.