The Philippines has made preparations to evacuate thousands of its citizens working in the Middle East as tension escalates, in the wake of the killing of Qassem Soleimani, a prominent commander of the Iranian Revolutionary Guards in a US raid.

Salvador Panilo, a spokesman for Philippine President Rodrigo Duterte, said on Tuesday that the president ordered the armed forces to provide air and naval capabilities to evacuate Filipinos from Iraq, Iran and neighboring Arab countries.

President Duterte has expressed grave concern about the possibility of a "long war" and told reporters that he has sent a special envoy to Tehran and Baghdad to obtain guarantees of safe passage for the Filipinos if they are evacuated.

"There are very many Filipinos working mainly in the Middle East. I am concerned, for Iran seems determined to take revenge that I envision will come," Duterte said in a speech on Monday.

Nearly 2.3 million Filipinos work in the Middle East in domestic work and in the construction, engineering and nursing sectors.

According to government data, approximately seven thousand Filipinos work and live in Iraq, and more than a thousand others in Iran.

Philippine Defense Minister Delphine Lorenzana, who heads a committee recently formed to prepare plans to evacuate Filipinos from the region, said the government is preparing aircraft to transport Filipinos who want to return to their country or move from Iraq and Iran to safer places.

"We can send transportation to get them," Lorenzana told reporters, noting that among the alternatives the government is considering to evacuate those wishing to return is the charter of a passenger ship.