Arsenal boss Arsene Wenger said he was still considering whether to take action against Chelsea counterpart Jose Mourinho for calling him "a voyeur".
Mourinho must now choose whether to continue the row
Mourinho sparked a row between the pair on Monday when he said Wenger was obsessed with Chelsea.
Wenger said he might take action, prompting Mourinho to claim he had a 120-page dossier on the Frenchman.
Now Wenger, asked if the chance of a formal complaint was alive, has said: "Yes, of course it is."
The Frenchman, speaking after his team's Champions League victory against Sparta Prague, added: "I don't know when I will decide."
Wenger did appear in one interview to draw a line under the whole affair, saying: "I feel that is behind us."
But in another interview the Highbury boss seemed to continue the spat.
He said: "At the moment, I'm focused on our games. Then we have a break and I will think about the situation.
"I love football and what is important for me is to focus on the game. But if I'm attacked then I respond.
"When I think it's not right, I will always do it, although the most important thing is to enjoy the game and to get people to enjoy the game we play."
It has been suggested in some quarters that the Football Association - which reportedly contacted both clubs on Wednesday seeking to end the row - might sanction Wenger and Mourinho.
Wenger said: "I don't know what I've done wrong so I don't know what the FA intend to do. I don't want to offend anyone but if you ask me a question and I don't answer it, I feel that I'm not polite with you."
The pair had earlier been urged by Wenger's chairman Peter Hill-Wood and League Managers Association (LMA), to end the spat.
"At the top level there is no animosity. I think it's best if people don't talk about individuals, little personal jibes are irrelevant," Hill-Wood told the Evening Standard.
"I don't think I should make comment about other chairmen. I'm sure that all this will blow over."
LMA chief executive John Barnwell said: "We will be making every effort to speak to them before the weekend and point out that it's not acceptable to have two senior managers having an acrimonious debate through the media.
Peter Hill-Wood has called for an end to the war of words
"It is two of our senior managers - albeit terrific senior managers - having a tit-for-tat.
"The more it's in the public domain, the more the conversation will be fuelled and fired.
"It's unfortunate there are too many incidents getting headlines off the pitch when what we want are more headlines on the pitch.
"Arsene and Jose have responsibilities. I don't expect them to shake hands but I expect them to put the thing to bed and let it rest, where it should be.
"They're both members of ours and highly respected, and we're disappointed this has come out in the public domain."
Bolton boss Sam Allardyce also condemned the pair.
Allardyce, a member of the LMA management committee, said: "I'm surprised.
"Two men as experienced and as talented as those two, going head to head publicly, is probably not the right thing to do.
"It's not right from their point of view, or either of the clubs' point of view."
Mourinho has said Chelsea possess "a file of 120 pages" full of Wenger's quotes about the Premiership champions over the last year.
Wenger has insisted that his only comments on Chelsea have been prompted by media questions put to him about the club.
But Mourinho also held out an olive branch to end the spat.
The Chelsea boss said: "It is time to stop because if we don't stop we are there. We are in the fight."