General messages are received with no dialogue shared -- "nothing tactical," Assad told BBC News.
No direct cooperation has occurred against the Islamic State since airstrikes began in September, he said.
Assad said he would refuse to join the U.S.-led coalition against IS.
On joining the coalition: "No, definitely we cannot and we don't have the will and we don't want, for one simple reason - because we cannot be in an alliance with countries which support terrorism," Assad said.
He added Syria would cooperate with other countries in fighting IS, but would not communicate with U.S. officials "because they don't talk to anyone, unless he's a puppet."
He criticized the United States' "pipe dream" to train and arm moderate rebels, stating there's no such thing as "moderate" rebels, only militants of the Islamic State and al-Nustra Front, an al-Qaida affiliate.
Assad also dismissed the accusation that the Syrian army uses barrel bombs – crude explosive devices filled with oil or forms of shrapnel sometimes loosely dropped from high altitudes via helicopter which may cause indiscriminate damage.
Assad's denial of the use of barrel bombs counters multiple documentations of events, including a report that more than 70 people died when barrel bombs hit Aleppo in December of 2013.
"There are no indiscriminate weapons. When you shoot you aim... you aim at terrorists in order to protect civilians," Assad said. "You cannot have war without casualties."
More than 200,000 people have died and three million displaced, according to the United Nations.
Although the priority on the region has switched to defeating the Islamic State, the U.S. government maintains its stance that Assad should resign.