DUBAI, United Arab Emirates >> Workers at refineries crucial for Iran’s oil and natural gas production protested Monday over the death of a 22-year-old woman, online videos appeared to show, escalating the crisis faced by Tehran.

The demonstrations in Abadan and Asaluyeh mark the first time the unrest surrounding the death of Mahsa Amini threatened the industry crucial to the coffers of Iran’s long-sanctioned theocratic government.

While it remains unclear if other workers will follow, the protests come as demonstrations rage on in cities, towns and villages across Iran over the Sept. 16 death of Amini after her arrest by the country’s morality police in Tehran. Early on Monday, the sound of apparent gunshots and explosions echoed through the streets of a city in western Iran, while security forces reportedly killed one man in a nearby village, activists said.

Iran’s government insists Amini was not mistreated, but her family says her body showed bruises and other signs of beating. Subsequent videos have shown security forces beating and shoving female protesters, including women who have torn off their mandatory headscarf, or hijab.

From the capital, Tehran, and elsewhere, online videos have emerged despite authorities disrupting the internet. Videos on Monday showed university and high school students demonstrating and chanting, with some women and girls marching through the streets without headscarves as the protests continue into a fourth week. The demonstrations represent one of the biggest challenges to Iran’s theocracy since the 2009 Green Movement protests.

Online videos analyzed by The Associated Press showed dozens of workers gathered at the refineries in Asaluyeh, some 575 miles south of Tehran, on the Persian Gulf. The vast complex takes in natural gas from the massive offshore natural gas field that Iran shares with Qatar.

In one video, the gathered workers — some with their faces covered — chant “shameless” and “death to the dictator.” The chants have been features across protests dealing with Amini’s death.

“This is the bloody year Seyyed Ali will be overthrown,” the protesters chanted, refusing to use the title ayatollah to refer to Iran’s Supreme Leader Ali Khamenei. An ayatollah is a high-ranking Shiite cleric.

The details in the videos correspond with each and to known features of the facility compared against satellite photos taken Sunday.

Iran did not acknowledge any disruption at the facility, though the semiofficial Tasnim news agency described the incident as a salary dispute. Iran is one of the world’s top natural gas suppliers, just after the U.S. and Russia.