Yemen’s former president on Saturday said he would leave for the United States to help calm tensions in his country after forces commanded by his son and nephew opened fire on more than 100,000 protesters marching into the capital. At least nine of the protesters died in the incident, according to doctors and activists.

The protesters had walked 200 miles over four days from the city of Taiz to Sanaa, the first march of its kind seen in Yemen, to pressure the government not to give the former president, Ali Abdullah Saleh, immunity from prosecution. When they reached the southern entrances to the capital, forces of the elite Republican Guard fired on them with automatic weapons, tear gas and water cannons.

In all, at least 500,000 protesters had joined the march by the time it reached Change Square in Sanaa, activists said.

At least eight protesters, including a woman, were killed and more than 200 injured, including 61 wounded by gunfire, according to two doctors at a protesters’ field hospital, Mohammed el-Qoutbi and Sadeq el-Shogaa.

Another protester was killed when security forces opened fire on about 500 protesters as they neared the presidential palace, activist Abdel-Karim el-Khaywani said.

The turmoil reflected the confused political situation in Yemen caused by Saleh’s slow-motion exit from power in the face of ­huge protests that have demanded his ouster since February.

Late last month, Saleh signed an agreement in which he would hand over his powers to his vice president, which he did Friday.

Saleh committed to stepping down in return for immunity, but opponents say he continues to wield influence through his loyalists and relatives still in positions of power, hampering the transition ahead of presidential elections set for Feb. 21.

On Saturday evening, Saleh told reporters that he would soon leave the country for the United States, though he did not specify exactly when. He had been expected to leave shortly after the deal was signed — ostensibly to undergo further treatment for injuries suffered in an assassination attempt in June — but officials say he has stalled.

“I will leave for the United States in the coming days. Not for treatment, but to get out of sight and the media to calm the atmosphere for the unity government to hold the presidential election,” he said.

Saleh said he would eventually return and pursue “political work as an opposition figure.”

— Associated Press