Referees' chief Mike Riley has admitted that four mistakes have been made by VAR in the Premier League so far this season.

Riley, a former referee and the managing director of the officials body Professional Game Match Officials Limited (PGMOL) addressed attendees at the Premier League shareholders' meeting in central London on Thursday, the PA news agency understands.

Riley pinpointed two penalties which should have been awarded to Manchester City and West Ham, and that a Newcastle goal should have been ruled out for offside.

It is understood that he told top-flight chairmen that Leicester midfielder Youri Tielemans should also have been sent off for his challenge on Bournemouth's Callum Wilson in the match on August 31.

The decision not to award City a penalty when David Silva was tripped in the box by Bournemouth's Jefferson Lerma on August 25 was judged to be an error, as was the failure to give a spot-kick to Hammers forward Sebastien Haller when he was fouled by Norwich's Tom Trybull in the match on August 31.

It is also understood that clubs discussed the length of the summer transfer window at the meeting.

Clubs voted two years ago to move deadline day, previously at the end of August, to a date before the season began.

The reasoning behind the decision at the time was that some clubs found potential player departures during the early weeks of the campaign disruptive.

But with no uniformity of deadlines across the continent, some managers – notably Tottenham's Mauricio Pochettino – have urged a rethink because players can still be lost to clubs abroad after the Premier League window closes.

The matter was raised at the meeting but no decisions were made and it will be discussed again in November.