Several air carriers are suspending flights and changing their routes to avoid airspace over Iraq and Iran amid tensions in region and after Wednesday’s deadly crash near Tehran killed all 176 people on board.

On Wednesday, the Boeing 737-800 bound for Ukraine’s capital city of Kiev crashed after departing from Tehran’s Imam Khomeini International Airport.

The plane was reportedly carrying 167 passengers from Canada, Iran, Sweden, Afghanistan, Germany and the UK, as well as 11 Ukrainian citizens, including the nine crew members, the country’s national security council confirmed.

Shortly after the crash, Ukraine International Airlines announced it is suspending all flights to Tehran. In its statement the company said that the plane underwent its last scheduled maintenance on Monday.

An investigation is already underway to determine the cause of the crash, and representatives from UIA are in direct contact with the families of those affected.

The airline also declined to comment on rumors that the plane was shot down.

Ukrainian authorities later announced that Kiev is banning flights over Iran from January 9 until the causes of the tragedy are clarified.

“As soon as the causes are clarified, the decision will certainly be reconsidered,” Ukrainian Prime Minister Oleksiy Honcharuk said.

European carriers started rerouting flights crossing the Middle East amid escalating tensions between the US and Iran. Air France said on Wednesday it suspends all flights over Iran and Iraq, the company told Sputnik.

Meanwhile, German’s Lufthansa said it had canceled its flight from Frankfurt to Tehran on Wednesday over situation in the region.

The Russian aviation agency, Rosaviatsia, sent an official recommendation for all domestic airlines to avoid flying over Iran, Iraq, the Persian Gulf and the Gulf of Oman.

The agency explained the move citing “existing risks for the safety of international civil flights.” Some companies have already done so, as Ural Airlines rerouted flight crossing Iran on Wednesday, according to TASS.

Russia’s S7 carrier said it is looking into changing the route of its flight from Russia’s Novosibirsk to Dubai to abide by the recommendation.

Earlier in the day, the US Federal Aviation Administration (FAA) said it would ban US carriers from operating over Iraq, Iran, and some Persian Gulf airspace after Iran attacked on US facilities in Iraq.

The agency said the restrictions were issued “due to heightened military activities and increased political tensions in the Middle East which present an inadvertent risk to US civil aviation operations.”

Shortly after the US non-binding warning, Australian carrier Qantas decided to will some flights to Europe until further notice.

Qantas’ non-stop flights between Perth to London frequently fly over Iran and Iraq and they were redirected to go over Afghanistan instead.

At the same time, Malaysia Airlines and Singapore Airlines said that their aircraft would avoid Iranian airspace.