Hearts head coach Ian Cathro has refused to comment on a potential deal for Christophe Berra but insists he knows exactly what he needs to improve his team when the transfer window opens.

Berra is a free agent after leaving Ipswich and the Edinburgh-born defender is expected to return to Tynecastle this summer.

Cathro said he understood where reports of an imminent deal came from but said he would not discuss specific players while Hearts still have games to play.

"The situation about players coming in or going out, for the next nine days until the end of the season I will not be commenting on," he said.

"Come the end of the season these things can start to be talked about. There'll be no official business in or out until the end of the season."

Despite not being drawn on individuals, the coach said he was hoping for a successful summer of recruitment, having made nine signings in January with mixed results. Cathro

"We'll look at, I think four players," he said. "I think four players will join us.

"The summer window is very different to the January window. It's easier partly because you have more time and also partly because it's naturally in between two seasons.

"We're not a club that's in a position in the market to have transfer fees and that determines that it's very difficult in January and significantly easier in the summer."

He added: "Our approach on this is something that we've been working quite hard on between January and now. It's to improve and broaden how we do that work across all markets that fit inside what we can reach.

"There's no limit to where we look. I've not signed a contract saying it will be four players. Maybe five, maybe three. I'm not making a global commitment to the number of players.

"We have time now to prepare these things. I came here on December 6. I had 25 days until the window opened and things were happening. Of course it was rushed, and now it's not."

Cathro is more than confident the targets he has identified will fit his plans for developing the team.

"We've lived through things and we've learned things which point us in a very clear direction," he said.

"I know exactly what we're going to bring and exactly what I want the squad to look like come the first competitive game of next season."