Soldiers opened fire at anti-government protesters Friday in northern Yemen, killing four people and wounding seven as demonstrations against longtime President Ali Abdullah Saleh again turned deadly.

Yemen has been rocked by weeks of daily anti-government protests, inspired by the uprisings in Egypt and Tunisia, and tens of thousands turned out in cities across the country calling for the ouster of Saleh, a key U.S. ally in the campaign against the al-Qaida terror network. He has promised to step down after national elections in 2013, an offer rejected by protesters.

Witnesses said the shootings in the town of Harf Sofyan occurred as soldiers tried to disperse thousands who took to the main street for Friday prayers.

Soldiers in an army post opened fire with heavy machine guns, believing the protesters were trying to attack the post, according to the witnesses, who spoke on condition of anonymity for fear of government reprisal.

Protesters threw rocks at the troops and called for Saleh to step down, shouting: "Leave! Leave!"

The town, located in Amran province, is a significant base for the Hawthi Shiite tribesmens who have waged an on-and-off struggle against the government for the last six years.

In the capital of Sanaa, tens of thousands assembled near Sanaa University to urge Saleh's ouster. Security forces watched the gathering closely, but it was not violent.

For the first time, the protesters included hundreds of women, filling a square and nearby streets.

In the southern city of Aden, tens of thousands of people carried the coffins of three people killed last week. Speakers at Friday prayers focused on the fall of the regime.

The main speaker during prayers at Sanaa University, Yahia Hussein al-Deilami, told the gathering that "deposing a tyrant is a religious duty."

Al-Deilami, a leader of the Shiite Hawthis, was sentenced to death three years ago but was pardoned by Saleh after the government reached agreement with the Hawthi rebels.

"This regime, a handful of corrupt officials, have encouraged bribes, corruption and plundering of the nation's wealth," he said.

Al-Deilami praised the youth revolution in Libya "against the tyrant Moammar Gadhafi" while crowds chanted for Saleh to resign _ just like former Egyptian President Hosni Mubarak.

"Ali, Ali before (the fall of) Moammar! Ali, Ali after Mubarak's fall!"

Hundreds of thousands of protesters also demonstrated in Taiz, Hadramawt, Ibb and Hudaydah in what was dubbed as the "Friday of the national cohesion."

In downtown Sanaa, several thousand government supporters carried pictures of Saleh and urged the opposition to respond to the president's call for dialogue.

In Egypt, the Yemeni Embassy said the ambassador was attacked Tuesday by armed men while traveling to the southern province of Assiut but he escaped unharmed.

The embassy said in a statement that Ambassador Abdel-Wali al-Shimiri, headed to Assiut to meet Yemeni students, was attacked while stopped in a car at a checkpoint on the outskirts of Assiut. Armed men tried to pull him from the car, but he was unhurt, the statement said.

Several guards were in another car, and they scuffled with the armed men, who were supported by others in three cars and managed to seize the guards' personal weapons, laptops and briefcases before they fled. One of the bullets fired by the gunmen hit the car.

Al-Shimiri continued on to Assiut, the statement added.