Daniel Agger
Barcelona will turn their attention to Agger after failing to sign Thiago Silva and Marquinhos. (Reuters)

Liverpool defender Daniel Agger is now Barcelona's prime transfer target as they bid to strengthen their defence after their hopes of signing Brazilian pair Thiago Silva and Marquinhos were extinguished.

The Denmark international was heavily linked with a move to the Nou Camp last summer as the La Liga giants sought to address their defensive frailties, but Agger would reject their overtures before signing a new contract with Liverpool.

Spanish newspaper El Mundo Deportivo now suggest the club will put all their efforts into signing the 28-year-old, after Brazil captain Silva reaffirmed his commitment to Paris Saint Germain, while 18-year-old Roma starlet Marqhinos looks primed to join his compatriot in the French capital.

With their defensive concerns more poignant than ever, Barcelona have made the recruitment of a centre half a top priority this summer and have relentlessly attempted to convince Brazil captain Silva to leave Paris Saint Germain for the Catalan giants.

Tito Vilanova yesterday confirmed his interest in the former AC Milan defender, but Silva has once again stressed that he fully intends to honour his contract with the Ligue 1 champions, which runs until 2017.

"Rumours? I have a four year contract with Paris Saint Germain and I will respect this," Silva said in quotes that appeared on the club's official website.

"The season will start as the last one ended. I will wear the jersey of Paris."

The La Liga champions have also been credited with interest in 19-year-old centre half Marquinhos. The Brazilian has only had one season with Roma but his commanding presence in the Giallorossi backline has seen him become one of Europe's most sought after talents.

Marquinhos' agent confirmed last week that Roma had received offers from Barca, PSG and Manchester United for his client, but the defender is now poised to join his compatriot Silva at the French champions in a deal reported to be worth €35m.

Liverpool are understood to have rejected two offers for Agger last summer and will be now bracing themselves for more bids. The club can ill-afford to lose their best defensive option with alternatives options severely limited.

The club are in the market to make defensive recruitments of their own with the futures of Martin Skrtel and Sebastien Coates in doubt, with Kolo Toure Brendan Rodgers' sole addition to a lightweight defence.