Officials in Baghdad and Washington remained unclear on Sunday about the fate of the Islamic State (Isis) leader Abu Bakr al-Baghdadi after a key aide was killed in a US air strike near Mosul.

A senior Iraqi official confirmed to the Guardian that the aide, Abdur Rahman al-Athaee, also known as Abu Sajar, was killed in the the attack late on Friday night, which hit a 10-car convoy south-west of the Isis stronghold.

Athaee was known to have been in almost constant contact with Baghdadi and officials deduced that his presence in the convoy likely meant that Baghdadi was with him.

However, monitoring of the group’s communications in the aftermath of the attack has revealed nothing to suggest that Baghdadi was killed. Officials have not ruled out that he may have been injured.

“We’re still looking at it very closely,” said an Iraqi intelligence official. “There’s nothing yet, and as time ticks on it may be less likely.”

Jihadi forums have remained mute since the strike took place. The death of Baghdadi would be difficult to keep quiet even among the tight discipline of Isis, which has proven difficult for Iraqi or international agencies to penetrate ever since it changed the modern face of the Middle East in June when it made rapid territorial gains in Iraq and seized Mosul, the country’s second largest city.

Iraqis officials claimed to have killed two senior Isis members on Saturday in a raid they carried out on the town of al-Qaim near the Syrian border. The raid took place on a house where senior leaders were meeting and is thought to have killed the overall leader of Anbar province, Adnan Latif al-Suweidi, and Isis’s leader in the Euphrates valley, Bashar al-Muhandi. Both held senior leadership positions in the organisation.

Targeted raids, carried out by the US and its Arab allies in the region, have proven effective in slowing the momentum of the group, according to Iraqi officials and one senior Isis member.However, they have failed to curtail its strategic aims.

The air strike near Mosul came hours after Barack Obama said he would double the number of US troops deployed to Iraq to reinforce the offensive against Isis. On Sunday, the US president said the troop surge will place the US on the front foot as it confronts the group.

In his first public comments since his surge announcement, Obama denied it represented a failure of early reliance on air strikes and said the deployment announced on Friday night “signals a new phase” in his campaign against Isis - also known as Isil.

“Rather than just try to halt to Isil’s momentum, we are now in a position to start going on some offensive,” he told Face The Nation on CBS.

“The air strikes have been very effective in degrading Isil’s abilities and slowing the advances they were making. Now we need some ground troops, Iraqi ground troops, to start pushing them back.”

The White House insists the new US troops will focus on training Iraqis to fight Isis and then coordinating air strikes, rather that being involved in what it calls an active combat role.

“What hasn’t changed is our troops are not engaged in combat, essentially what we are doing is we are taking four training centres with coalition members that allow us to bring in Iraqi troops, some of the Sunni tribes that are still resisting Isil, giving them proper training, proper equipment, helping them with strategy, helping them with logistics,” said Obama.

Iraqi forces have performed abysmally since Isis stormed into Mosul on 10 June. In the chaotic two days that followed, up to six divisions fled, surrendering their US-supplied advanced weapons. Since then, Shia militias have increasingly taken prominence in most frontlines across the country.

“We will provide them with close air support once they are prepared to start going on the offensive against Isil, but what we won’t be doing is having our own troops do the fighting,” he added.

But the president also refused to rule out further increases in military engagement in Iraq and Syria, which already include daily bombing raids on Isis in both countries.

“As the commander-in-chief, I am never going to say never,” he said when asked whether more troops would be sent. “But what the commanders who presented the plan to me say is that we may actually see fewer troops over time because now we are seeing coalition members starting to partner with us on the training and assist effort.”

Obama insists this time it will be different because attacks on Isis will only be led by Iraqis.

“What we learned from previous engagement in Iraq is that our military is always the best, we can always knock out any threat, but then when we leave that threat comes back,” he said.