SANAA, Yemen — Security forces and plainclothes gunmen opened fire on crowds of Yemenis marching through a southern city Monday, killing at least 17  and wounding dozens, in an intensifying crackdown against the uprising against the 32-year rule of President Ali Abdullah Saleh.Witnesses described troops and gunmen, some on nearby rooftops, firing wildly on thousands of protesters who marched past the governor’s headquarters in Taiz in the second straight day of violence in the southern city. Some — including elderly people — were trampled and injured as the crowds tried to flee, witnesses said.

Violence has swelled in recent days amid frustration over behind-the-scenes efforts to convince Saleh to step down in the face of a nearly two-month-old uprising. The United States and European countries have been contacting Saleh and his opponents, trying to find a formula for the president to leave his post with a stable transfer of power, an opposition spokesman said.

Monday afternoon, U.S. State Department spokesman Mark Toner called the latest violence in Yemen “appalling.”

The New York Times on Monday said Washington had “quietly shifted positions” and “concluded that [Saleh] is unlikely to bring about the required reforms and must be eased out of office.”

Speaking at his daily briefing, Toner sought to play down the New York Times report. Asked if the United States believed Saleh must go, Toner replied: “That’s not necessarily a decision for us to make.” He said the United States was talking to the government and the opposition in the hope of achieving “a peaceful solution.”

Saleh has been a key ally of the United States, which has given him millions in counterterrorism aid to fight al-Qaida’s branch in the country, which has plotted attacks on American soil. So far, Washington has not publicly demanded that he step down, but the diplomatic effort was a clear sign that the Americans have decided the danger of turmoil and instability outweighs the risks if Saleh leaves.

Mustafa al-Sabri, a spokesman for a coalition of opposition parties, said U.S. and European diplomats who had been in contacts with Saleh had asked the opposition for their “vision” for a transition. In response, the opposition over the weekend gave the Americans a proposal that Saleh step down and hand his powers to his vice president, who would then organize a process for rewriting the constitution and holding new elections, al-Sabri said.

In this regard US has stepped up its efforts to implant its team which is already in contact as  Opposition Parties members who are already in terms with US , to form a new government , as and when Saleh steps down, US should not loose its interest in Yemen. As Saleh has been a US ally , and when he will leave the office , he will hand over the power to only the US sponsored Team. So there is no change in the policies, and the Policies remains the same ,while the faces change.

But the 65-year-old president has dug in against the idea.

On Sunday, Saleh took a tough line, saying no negotiations could be held without a “halt to all protests and the mutiny by some units in the military.”

“We are prepared to explore the peaceful transfer of authority in the framework of the constitution. But arm-twisting will absolutely not work,” he said.

Harsh crackdown
The U.S. Embassy has not commented on its efforts, saying only in a statement over the weekend that “Saleh has publicly expressed his willingness to engage in a peaceful transition of power; the timing and form of this transition should be identified through dialogue and negotiation.”

A diplomat in Sanaa said on Monday the focus for now was still on talks, and that public calls to stand down — which have only so far come from France — were premature.

“It depends on developments in the coming days. This is one of the options that all capitals have if they want,” he said.

“At the moment, diplomatic parties are working behind the scenes to encourage an agreement on political transition between Yemeni parties. Other options are being kept at the moment in the drawer,” the diplomat said.

If Washington were to call on Saleh to go, “I’m not sure if he (Saleh) would immediately cave in,” he added.

Saleh has managed to cling to power even after many of his top allies in the government and military abandoned him and joined the opposition because of the harshness of his crackdown on the protesters. The opposition has been holding continual protest camps in main squares of the capital Sanaa and other cities around the country, and hundreds of thousands turned out for the biggest and most widespread marches yet on Friday. At least 97 people have been killed since demonstrations began Feb. 11.

The violence in the mountain city of Taiz began when thousands of protesters marched down its main street toward Freedom Square, where demonstrators have been camped out surrounded by security forces.

As the march passed the governor’s headquarters, troops stationed there blocked the procession, and clashes broke out, with some protesters throwing stones, witnesses said.

Troops on nearby rooftops opened fire with live ammunition on the crowd and the marchers then turned to besiege the governor’s headquarters, said Bushra al-Maqtara, an opposition activist in Taiz, and other witnesses.

“It was heavy gunfire from all directions. Some were firing from the rooftop of the governor’s building,” said one man in the crowd, Omar al-Saqqaf. He said he saw military police load the bodies of two slain protesters into a car and then speed away.

The military has clamped down on the city of nearly half a million, about 120 miles south of the capital, Sanaa. For a second day, tanks and armored vehicles blocked entrances to the city to prevent outsiders from joining the protests. They also surrounded Freedom Square, bottling up the thousands in the protest camp there and arresting anyone who tries to exit.

Saleh’s top security official in Taiz, Abdullah Qiran, to oversee security in Taiz, is accused by demonstrators of orchestrating some of the most brutal crackdowns against demonstrators, particularly in the southern port town of Aden, where he was previously stationed until his transfer several weeks ago. On Sunday, police attacked a march by thousands of women in Taiz, sparking a battle with a separate group of male protesters.

Marches in solidarity with the Taiz protesters erupted in the cities of Mukalla, in the east, and Hodeida, on Yemen’s western Red Sea coast. In Hodeida, protesters tried to march on a presidential palace in the city but were blocked by security forces, who opened fire with tear gas and live ammunition, said activist Abdel-Hafiz al-Abbasi.