Watford have announced the signing of Italy international Marco Motta, subject to international clearance.
Mark Noble has signed a new deal with West Ham which will keep him at the club until the summer of 2020.
The Arsenal Supporters' Trust fear that Arsene Wenger's "obsession" with developing young players is damaging the club's chances of winning silverware.
AST have issued a strongly-worded statement outlining their belief that offering Wenger a new contract would be "inappropriate" and that any decision on extending his stay beyond 2014 should only be made after the transfer window closes.
The group's key concern is Arsenal's failure to recruit any new players other than little-known France Under-20 free agent Yaya Sanogo, with attempts to sign Gonzalo Higuain, Wayne Rooney and Luis Suarez proving unsuccessful.
It is understood that a bid for Newcastle midfielder Yohan Cabaye has been rejected, adding to the sense of frustration.
"The failings we highlighted in Arsene Wenger holding far too much power have only been amplified in recent weeks. These must be addressed as a matter of urgency," the AST's statement read.
"For now the club's entire focus must be on using the remaining days of the transfer window to strengthen the team significantly."
Arsenal are reported to have a budget in the region of £70million for new players but with only 12 days of the window remaining, they have yet to spend a penny of it.
Saturday's 3-1 home defeat by Aston Villa and a lengthy injury list that now includes Alex Oxlade-Chamberlain has brought their lack of transfer activity into sharp focus and Tim Payton, a spokesman for AST, is critical of Wenger's prudence.
"We don't know what's going on but clearly there's a manager that by his own words isn't a big fan of spending money on strengthening the team through expensive player acquisition," Payton said.
"His apparent obsession with being a developmental manager is in danger of holding the club back.
"I'm absolutely certain that Arsenal will invest in players before the window closes, but will they be players of the required quality we want to compete to win trophies rather than once again competing to come fourth?
"Arsenal fans pay some of the highest ticket prices in world football and we want to see that invested in top players."
AST hold majority shareholder Stan Kroenke "ultimately responsible" for the situation at Arsenal and are unsatisfied with the boardroom structure at the club.
Payton denies the timing of the statement is a knee-jerk reaction to the Villa defeat.
"It's actually the continuation of concerns we have been raising with the club," Payton said.
"We've been raising concerns about the lack of football people in the boardroom and who's managing the manager and his expenditure for a long time.
"Why it was issued after the Aston Villa game is because we're more than three quarters of the way through the transfer window without a penny being spent despite the huge amounts of cash held in reserve.
"Our squad is palpably not good enough to represent Arsenal effectively in games at the moment. We felt there had to be a challenge to that."
Arsenal head to Istanbul for Wednesday night's Champions League first-leg play-off against Fenerbahce reeling from their shock loss to Villa and the knee injury sustained by Oxlade-Chamberlain during the match.
It is feared the England winger could be out for up to six months with ligament damage, casting a cloud over the Gunners' preparations for a critical match.
Mikel Arteta, Nacho Monreal and captain Thomas Vermaelen were sidelined for the opener at the Emirates Stadium and with the UEFA deadline for registering new players having passed, Wenger can only rely on the dwindling options already available to him.