The summer transfer window has now begun, with rumours and speculation continuing to swirl as Manchester City eye possible reinforcements.

The 2018-19 champions did not bring in a single player during the January transfer window, despite suffering a defensive shortage for much of the 2019-20 campaign, but they have already started their business for the summer.

Here, Sports Mole rounds up the latest news on possible comings and goings at the Etihad.

Friday morning's Manchester City transfer talk news roundup:

Owen Hargreaves urges Manchester City to sign Inter Milan star Lautaro Martinez

Former Manchester City midfielder Owen Hargreaves has urged the club to sign Inter Milan forward Lautaro Martinez as a replacement for Sergio Aguero.

Martinez scored twice for Inter in their 5-0 semi-final thrashing of Ukrainian side Shakhtar Donetsk in the Europa League on Monday night, increasing his goal tally to 21 for the current campaign.

Argentine compatriot Aguero, who has just one year left on his contract at City, has a desire to play in his native country again before hanging up his boots and Hargreaves insists that Martinez would be a perfect replacement for City's all-time leading scorer.

"I know Manchester City are looking for a replacement for Aguero, Martinez is your guy," Hargreaves told BT Sport.

"He's got everything. He's skilful, a lethal finisher. He's got everything – [he's just] 22 years old.

"He's the type of player whether at Barcelona or Manchester City they're going to get a really special player."

Martinez has been heavily linked with a move to Spanish giants Barcelona this summer, with several reports stating that he remains one of the Catalan club's primary transfer targets.

Lionel Messi 'tells Ronald Koeman he has doubts over Barcelona stay'

Lionel Messi reportedly told new Barcelona boss Ronald Koeman on Thursday that he has serious doubts about remaining at Camp Nou this summer.

The Argentina international is believed to have held a face-to-face meeting with Koeman to discuss his future amid suggestions that the attacker could seek a move away from the Catalan giants ahead of next season.

According to RAC1, Messi informed Barca's new head coach that he was considering an exit and currently sees himself 'more out than in' at the club.

The team's shocking 8-2 defeat to Bayern Munich in the quarter-finals of the Champions League allegedly had a huge impact on Messi, whose current deal at Camp Nou is due to expire next summer.

Manchester City and Inter Milan have both recently been credited with an interest, and it is believed that the former would be the favourites to sign him should he seek pastures new.

The 33-year-old scored 31 times and registered 26 assists in 44 appearances for Barca in 2019-20, but he only managed three goals in the Champions League.

More transfer news from Manchester City:

Wolverhampton Wanderers 'willing to sell Adama Traore this summer'
Wolverhampton Wanderers are prepared to listen to offers for Adama Traore this summer amid claims of interest from Liverpool and Manchester City, according to a report. Read more.

Manchester United to use Sergio Romero in Jack Grealish deal?
Manchester United could offer Sergio Romero to Aston Villa as part of a move for English attacker Jack Grealish, according to a report. Read more.

Aston Villa 'confident of keeping Douglas Luiz amid Manchester City links'
Aston Villa are reportedly confident of keeping hold of Brazilian midfielder Douglas Luiz despite alleged interest from Manchester City. Read more.

Lionel Messi 'meets with Ronald Koeman to discuss Barcelona future'
Lionel Messi met with new Barcelona boss Ronald Koeman on Thursday, according to a report. Read more.