The terrorist sniper team was struck by a "direct hit" as two Tornado GR4s flew over western Iraq.
The two fighter jets were among four to set off from RAF Akrotiri in Cyprus overnight. Two jets carried out reconnaissance in Syria while two others flew over western Iraq to provide support for the Iraqi army.
RAF fighter jets 'silenced' IS militants firing at troops in Iraq
The MoD said in a statement: "Overnight on December 3 to 4, Tornado GR4s from RAF Akrotiri conducted missions over Syria and Iraq. Two GR4s flew an armed reconnaissance patrol over eastern Syria, gathering intelligence on terrorist activity.
"A second pair of GR4s patrolled over western Iraq, where they provided close air support to Iraqi forces engaged in combat with Daesh in and around Ramadi.
"A terrorist sniper team opened fire from a compound on Iraqi troops, but was silenced by a direct hit from a Paveway IV guided bomb."
More fighter jets have been sent to RAF Akrotiri on Cyprus ahead of further strikes in Syria and continued raids in Iraq against ISIS.
A RAF Typhoon arrives at RAF Akrotiri
David Cameron is insisting that British war planes can help to bring about a political settlement in Syria.
During a visit to Bulgaria, Cameron said: "We've now got more Tornados and more Typhoons in Cyprus ready to take action both over the skies of Iraq and over the skies of Syria because we have to defeat Daesh wherever it is.
"Bringing everyone around the table and trying to get a political settlement is absolutely crucial but we can't wait for that to happen before we start taking action against Daesh, as we have after the vote and as we will continue to do."
He added: "The strikes actually help to bring about a political settlement because the strikes take the action to Daesh, which is everyone's enemy, and we do need to have a moderate opposition in Syria that can be part of the future government.
"So the political process and the action against Daesh to keep us safe at home go hand in hand."
On Wednesday, MPs voted to launch airstrikes against IS forces in Syria.
Just hours after the vote, the RAF completed its first mission in Syria, striking an IS-controlled oilfield in war-stricken state.