"The international federation has to make sure the security is good enough."
An assistant coach, press officer and driver were killed and two players were shot and injured in Friday's attack. Togo were reported to have pulled out of the tournament, although the issue has become clouded with conflicting reports emerging from Angola.
Everton have both Joseph Yobo and Yakubu Aiyegbeni away at the tournament with Nigeria.
Manager Moyes said: "The club have contacted them and they're okay, but obviously it's a concern for football - not just for the African Nations Cup, but for all sorts of tournaments.
"I think everyone had concerns about Angola, but we are trying to give everyone an opportunity, that's what we should be doing."
There are a total of 31 Premier League players in Africa for the tournament, which starts on Sunday when hosts Angola take on Mali.
The Football Association said it had been in "continual contact" with all English clubs who have players involved, as well as the Premier League, the League Managers' Association, Fifa and the Confederation of African Football.
"All of English football would like to offer our sincere condolences to everyone connected with the Togolese squad," the FA said in a statement.
"We will do all we can to ensure the welfare and safety of all Premier League players in Angola representing their countries."
Tottenham boss Harry Redknapp does not have any players at the tournament but said: "It's frightening.
"It's worth considering calling the whole thing off. We can't just sit around and wait for the next shooting."
Aston Villa manager Martin O'Neill expressed his shock at the incident but was relieved his Togolese midfielder Moustapha Salifou was not among the injured.
"The club have been in contact with him and he has reassured us that he is OK but he is extremely shocked and upset, which he would be in these circumstances," said O'Neill.
"Something like that is going to live with him for a very long time, if not for the rest of his life."
Having witnessed such a traumatic scene, O'Neill insisted Villa will do everything possible to help Salifou recover from the attack.
"It was very, very harrowing and he is actually a very sensitive lad," he told BBC Radio 5 live's Sportsweek programme.
"He's very popular in the dressing room. He's very quiet. He's got a wry sense of humour, but he's an exceptional fellow and I think he will take this very badly indeed.
Moustapha Salifou was on the bus when the attack happened
"We have a number of people at the football club who I think can help him.
"Some of the players who are quite close to him will give him as much counselling as possible but I'm hoping in time he will be able to settle down and get back to playing."
Portsmouth have four players at the tournament and spokesman Gary Double said they had sought reassurance from the FA and Fifa about security.
"Our players' safety is paramount and if that can't be guaranteed the players should be sent home," he said.
Professional Footballers' Association chief executive Gordon Taylor said Premier League clubs should not be able to dictate whether their players were sent home.
He told BBC Radio 5 live: "Bearing in mind what has happened, for English clubs to expect players to come home from any other team apart from Togo would be too far.
"It's a decision to be taken by the clubs but that could be in conflict with the African Confederation and Fifa and that is the dilemma of the day, not just in sport, but in many other issues regarding terrorism.
"Do we try to continue life as normally as possible in order to win on the day?
"We need to know the whole circumstances and have a proper inquiry, but you can understand clubs asking for players to come home after such an incident.
"Clubs release their players under Fifa regulations but they have every right to expect that the security issues and safety is going to be paramount and if that is not the case, they have a serious reason to withdraw them."
Hibernian boss John Hughes has defender Sol Bamba on international duty with Ivory Coast, grouped with Togo in Cabinda.
Asked if he wanted to pull Bamba out, Hughes said: "No, I'll put all my trust in Fifa and the tournament organisers."
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