By Graham Keeley

BARCELONA Spain's Socialists have emerged with one seat fewer after counts of votes from abroad in last week's election, making it harder for them to be able to form a left-wing coalition as they would need the support of hardline Catalan separatists rather than just their abstention, analysts told Reuters on Saturday.

In Sunday's close-fought election, neither the left or right blocs won enough seats to form a majority and Catalan separatist parties Esquerra Republicana de Catalunya (ERC) and Junts emerged as kingmakers, both controlling seven seats each.

Esquerra is seen as likely to back Socialist Prime Minister Pedro Sanchez but if the fresh seat count is confirmed by the electoral commission it appears that Junts, the more hardline of the Catalan parties, would also have to actively support him for him to be able to form a government.

Sanchez called last week's election early after left-wing parties were battered in local and regional elections in May, hoping to catch the opposition off guard. The left emerged stronger than opinion polls had predicted but Sanchez, now in a caretaker role, faces an uphill task forming a government.

Counting of votes from over 233,000 Spaniards living abroad handed one seat in Madrid to the PP that had been awarded to the Socialists in the initial vote count, the PP and Socialists said on Saturday. This was not yet officially confirmed by electoral authorities.

To form a government, an absolute majority is needed in a parliamentary vote in the 350-seat Congress. If neither bloc is able to secure that, there is a second vote in parliament and the side with the most votes wins by a simple majority.

According to the revised seat count, the PP could muster a total 171 votes, including 137 of its own, 33 from the hard-right Vox party and one from the Union of the Navarran People, a regional party. No other parties have said they will support an administration that includes Vox.

A spokeswoman for Canarian Coalition, a regional party with one lawmaker, told Reuters on Saturday it would not support a government containing Vox but had not decided if it would support Sanchez.

For his part, Sanchez could muster 171 seats with 121 seats from the Socialists and the support of the far-left Sumar party (31 seats), Esquerra (seven), the Basque separatists EH Bildu (six), the Basque Nationalist Party (five) and the Galician Nationalist Bloc (one).

On Friday, before the seat change occasioned by the foreign vote count, the left bloc could look forward to 172 votes, while the PP and allies Vox and UPN could only muster only 170. This meant Sanchez only had to persuade Junts to abstain, to be voted back into power with a simple majority.

Now, depending on how the Canaries party decides to act, Sanchez is likely to need at least one vote from Junts to beat the PP and its allies.

"This will make it harder for Sanchez because if he needs their votes, it will give Junts more power to demand things in return," Pablo Simon, a political analyst at the Carlos III University in Madrid, told Reuters.

SEPARATIST CONDITIONS

Junts, which takes a harder line on independence for Catalonia than the ERC, said on Monday its conditions for helping Sanchez get over the line were permission to hold a referendum in Catalonia on independence and an amnesty for all separatists facing legal charges related to a failed independence bid by the region in 2017.

The holding of a referendum would need a change in the Spanish Constitution and the vote of a majority of lawmakers which is certain not to happen.

Alberto Nunez Feijoo, the PP leader, is still determined to try to form a right-wing coalition.

"Feijoo wants to govern for all Spaniards," Pedro Rollan, the PP regional coordinator, said in Madrid on Saturday.

Sumar leader Yolanda Díaz called on all "progressive forces" to support Sanchez.

"I believe that political groups must rise to the occasion, and I appeal to the progressive and democratic forces of the country to guarantee (Sanchez) is voted in as prime minister," she said in an interview with Italian newspaper La Repubblica published on Saturday.

(Reporting by Graham Keeley; Additional reporting by Alvise Armellini in Rome; Editing by Frances Kerry)