"We will be asking the (English) FA to talk to FIFA to ensure the players' safety," Portsmouth's director of communications Gary Double told Reuters on Friday.
"That is paramount and if the players' safety cannot be ensured, then the players should be sent home."
A bus driver was killed in the gun attack shortly after the Togo team crossed the border into the Cabinda enclave, where they are due to play their first group match on Monday.
Nine other people, including two players, were wounded in the attack, said a Togo team official.
The English FA said it would do all it could to ensure the clubs were made aware of the situation at the Nations Cup, the tope African football tournament which runs from January 10-31.
"Following the terrible attack on the Togo national team in Angola, the Football Association is in contact with various English clubs who have players involved in the African Cup of Nations," the FA said in a statement.
"We will continue to ensure we are kept up to speed with all developments and do all we can to assist our clubs and those players involved. The FA is currently contacting various organisations, including FIFA."
Manchester City were among the English clubs worried about their players' safety.
"We are currently in talks with the Football Association over what may happen next," City said on their website.
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