Ipswich's late equaliser has virtually relegated Leeds, who trail Hull by three points and have a vastly inferior goal difference with one game to play.
It is still mathematically possible for Leeds to stay up, but they would need to win their last game by at least eight goals, and for Hull to lose.
Richard Cresswell opened the scoring for Leeds but Alan Lee glanced in a header on 88 minutes to cancel it out.
A pitch invasion and 30-minute delay followed before the match could finish.
Referee Michael Jones had led the players from the field with several minutes of time added on still to play.
And when the players came back onto the field to see out the game, referee Jones blew for full-time within a minute and promptly sprinted for the tunnel.
Football League spokesman John Nagle on the crowd trouble:
"These actions by a minority of Leeds supporters could have serious consequences for the club."
"Clearly, passions will run high at this stage of the season.
"However, it is deplorable for supporters to enter the field of play at any time.
Leeds boss Dennis Wise
"It's a sad enough day as it is. I don't want to talk about the pitch invasion."
Ipswich manager Jim Magilton:
"It was a shambolic but brave decision to come back out.
"I was involved in something similar at West Ham when the game was called off. This one should have been called off.
"It was a poor decision. The players were worried about going back out. If any of them had got hurt, I would have been knocking on the referee's door."
Leeds: Ankergren, Richardson, Foxe, Rui Marques, Gray (Kandol 88), Blake (Moore 82), Kishishev, Thompson, Lewis (Robbie Elliott 77), Healy, Cresswell.
Subs Not Used: Stack, Johnson.
Booked: Thompson, Foxe, Blake.
Goals: Cresswell 12.
Ipswich: Supple, Wright, Bruce, Wilnis, Harding, Peters (Clarke 76), Garvan, Williams (O'Callaghan 63), Roberts, Jeffers (Walters 67), Lee.
Subs Not Used: Price, Richards.
Booked: Roberts, Garvan, Clarke.
Goals: Lee 88.
Ref: N. Jones. (England).