Updated

Yemeni protest leaders announced the formation of a so-called shadow government Saturday in a move to take the lead in the fight to oust President Ali Abdullah Saleh's regime.

The new group seeks to create a unified leadership for the tens of thousands of demonstrators who have filled public squares across Yemen for five months.

But it was unclear how the group planned to assert authority and it was unlikely to significantly increase pressure on Saleh. The embattled president clung to power even after he traveled to Saudi Arabia for medical treatment of wounds sustained in an assassination attempt more than a month ago.

Saturday's announcement by the protest leaders came a day before the 33rd anniversary of Saleh's ascension to power. Officials in Saleh's ruling party initially said he may return to Yemen for the occasion, but later played down the possibility, saying only doctors can make that decision.

During Saleh's absence, Yemen descended into further chaos as militant groups try to exert control over outlaying provinces. Also, political negotiations over a transfer of power have stalled. Saleh has refused to sign a regionally brokered deal that offers him immunity from prosecution in exchange for leaving office.

Protest leader Tawakul Karman told reporters in Yemen's capital of Sanaa on Saturday that the new 17-member council includes former ministers, prominent business people and civil society leaders. Among those named to the council were Gen. Abdullah Ali Aleiwa, a former defense minister, and Haidar Abu Bakir al-Atas, a former prime minister.

Karman said the council will soon choose a leader who will appoint a shadow Cabinet of technocrats. The council will also announce a 501-member "national assembly" that will draft a new constitution.

Karman, who is a senior member of the opposition Islamic fundamentalist Islah Party, said the body seeks to "protect the unity of the country before it completely collapses." When asked how the new body will exercise power while Saleh's government remains in place, she said it would count on "revolutionary decisiveness."

Abdu al-Janadi, a spokesman for Saleh's government, said the announcement "pours gas on the fire."

He said that Saleh is "the legal, democratically elected president, and an alternative will only come though elections, not through an illegal coup."

The new political body also highlights the gap between Yemen's protesters and Yemen's official opposition parties, which protesters say were late in joining the anti-regime rallies inspired by those in Tunisia and Egypt. Many protesters criticize the parties for seeking to negotiate Saleh's exit instead of trying to bring down his entire regime.

Officials from the mainstream opposition movement known as the Joint Meeting Parties declined immediate to comment. The opposition movement previously announced it is studying the formation of its own transitional council.

Also Saturday, Yemeni officials said oil has begun moving though a pipeline in the Marib province for the first time since local tribesmen attacked it in March.

The attack by anti-Saleh tribesmen had stopped the daily flow of 100,000 barrels through the pipeline. The tribesmen had also prevented the government from making repairs.

However, the tribe allowed government engineers to enter the area on Thursday to work on the pipeline, according to local tribal leader Ali Shibwani. He said the tribe relented because it was concerned about growing fuel shortages.

Oil officials confirmed that oil started flowing again Saturday. They spoke on condition of anonymity because they were not authorized to brief the media.