Midfielders Huws, 20, and Rusnak, 19, joined Blues in January and the pair have both made four appearances for Lee Clark's men.
"It's brilliant news because the two of them have made a big impact," Clark told the club's official website.
"Both on and off the pitch, Albert and Emyr are really popular with the lads and I'm delighted that both Manchester City and the lads have agreed to stay until the end of the season.
"We need them like we need all the players we brought in during January, which is why it was such a blow when we lost young Tom Thorpe from Manchester United so early into his loan.
"Even on Saturday (against Huddersfield), it was probably Emyr's quietest game of the lot but he was still very influential for us in terms of some of the good things that we did do well.
"Albert has been a bright player for us. We like him, we like his personality and we think he can do good things for us for the remainder of the season."