Answering the question whether further attacks on Syria should be expected, Johnson said in an interview with the BBC broadcaster that no proposals on new strikes were being considered at the moment.
"There is no proposal on the table for further attacks because so far, thank heavens, the Assad regime has not been so foolish to launch another chemical weapons attack," Johnson said.
"If even such a thing [a chemical attack] were to happen, then clearly, with allies, we would study what the options were," he added.
"Obviously our prime consideration has to be the safety of our serving men and women and of course the effectiveness and speed of the operation. And there is plenty of precedent for getting it done in this way," he said.
On Friday night, the United States, France, and the United Kingdom launched strikes on a number of targets in Syria in response to the alleged chemical incident in the Damascus' suburb of Douma. The Western states have accused government forces of President Bashar Assad of an attack with the use of chemicals in Douma. Syrian authorities denied any involvement in the attack, and invited the experts from the Organization for the Prohibition of Chemical Weapons (OPCW) to investigate into the reports.
According to the Russian Defense Ministry, the three countries fired over 100 cruise and air-to-surface missiles, most of which were shot down by Syrian air defense. According to Damascus, which has repeatedly said it had eliminated its chemical weapons stockpiles, the attack damaged Syrian infrastructure, and left three civilians injured.
