By Gavin Jones
ROME (Reuters) - Rome Mayor Ignazio Marino, tainted by an expenses scandal, on Thursday withdrew the resignation he tendered three weeks ago under pressure from Prime Minister Matteo Renzi, causing ructions in their Democratic Party (PD).
Marino continues to lack the support of Renzi and his decision to battle on in office opens up a potentially damaging conflict for the prime minister.
"The mayor of Rome, Ignazio Marino, has signed the letter in which he withdraws his resignation," said a brief statement from city hall.
Marino, who has steadily lost popularity since being elected in 2013, denied any wrongdoing when he announced his resignation on Oct. 8, following allegations that he had tendered inaccurate claims for several restaurant meals.
He never formally left office and in his original resignation letter, he said he could reverse his decision if he felt the political mood had shifted.
However, that does not appear to have happened.
Renzi has distanced himself openly from Marino, saying he had "lost the confidence of the Romans", and the PD said earlier on Thursday it would pull all its councillors from the city government if Marino withdrew his resignation.
It was not clear how Marino, a 60-year-old former liver surgeon, hoped to continue to govern the Rome administration without the backing of the PD councillors.
The tensions in Rome city hall and the stand-off between Renzi and Marino have dominated Italian news headlines for weeks.
Many Romans complain city services such as trash collection, road maintenance and transport have got worse under Marino.
The mayor's supporters say he inherited a disastrous situation from his right-wing predecessor, who is under investigation for corruption. They have held several rallies in his defence since he first tendered his resignation.
The standoff comes just weeks before the start of a Catholic Holy Year, declared by the pope, which is expected to draw millions of visitors to the capital. Work on preparing the creaking city for this influx has barely started.
After Marino resigned, Renzi said he would set up a "dream team" of administrators to shepherd the city through the early months of the Holy Year until new mayoral elections could be held next spring or early summer.
On Nov. 5 a high-profile trial will begin in the city, bringing to court dozens of politicians and businessmen arrested at the end of last year for allegedly rigging public contracts in areas from Roma camps to refuse management and immigrant centres.
Marino is not implicated and is expected to appear at the trial to present the city as an injured party.
With the mainstream parties on the left and right weakened by corruption scandals, polls say the anti-establishment 5-Star Movement is now the city's most popular party and would be in pole position if new mayoral elections were to be held soon.