Walid al-Muallem, Syria’s longstanding foreign minister, became the irascible face of the defensive, authoritarian regime of President Bashar al-Assad during the country’s near decade of gruelling civil war.

Seen by diplomats as a professional who never deviated from the party line, the top foreign official, who has died aged 79, became less visible as the bloody conflict wore on through the 2010s. As peace negotiations between regime and opposition forces collapsed, Syria’s pariah status solidified and Russia, Iran and Turkey increasingly began calling the shots, Muallem seemed an immovable regime stalwart. Yet “loyal or not loyal, it’s like saying a believer or a non-believer,” observed Bassam Barabandi, a former Syrian diplomat who defected in 2013. “We cannot know his mind.”

Muallem was born in 1941, son of a traditional Damascene Sunni family considered to be from “inside the walls” — an expression referring to the capital’s walled old city and denoting authentic Damascene heritage.

His education was bookmarked by remarkable political turbulence. Muallem began school shortly after Syria gained independence from French rule and graduated in economics from Egypt’s Cairo university in 1963, the same year the Arab Socialist Ba’ath party of Hafez al-Assad, Bashar’s father, seized power.

Like many aristocratic young men, Muallem joined Syria’s foreign service in 1964, taking postings from Africa to Europe. Twenty-six years later, the careful networker landed the ambassadorship in Washington, where he spent nearly a decade navigating fraught US relations. Hafez al-Assad then picked Muallem as assistant foreign minister. After Bashar took power in July 2000, following his father’s death, he promoted Muallem to minister in 2006, adding deputy prime minister in 2012.

The minority Alawi dictator’s choice of a Sunni Damascene for the high-profile role “was very carefully manicured”, said Joshua Landis, Middle Eastern history professor at the University of Okhaloma, who has studied Syria’s foreign ministry. Muallem’s influence was limited, he added: “the foreign ministry was always a face of the regime, which is ultimately a security state.”

But Muallem “was good at PR”, said one Syrian journalist, who recalled him as “funny” and “pleasant,” often joking with reporters at press conferences. Such bonhomie was rarely displayed on the international stage as the war ground on. Muallem became better known for bitter throwaway quips: “we will forget that Europe exists on the map” was his response to EU sanctions.

“I dealt with a lot of foreign ministers,” said Robert Ford, an American diplomat who was US ambassador to Syria in 2011. “In many ways Muallem was the least friendly.”

While Syria weathered contentious international relations for decades, the regime’s vicious crackdown on peaceful protesters in 2011 crossed a line. One Arab diplomat who co-operated with Muallem for years before the uprising and “used to like him a lot” said that after that “he fell from grace”.

Yet Mr Ford recalled a May 2011 meeting in which Muallem “let the mask slip a little bit”. Muallem asked assembled British, French and American envoys to “help [the regime] set up a channel of negotiation with the opposition leaders”, he recalled. Although the communications were ruined by regime security services, Mr Ford thought Muallem was in earnest at the time.

Muallem represented the belligerent regime at UN-brokered peace talks, including at an infamous 2014 incident where he badgered former UN secretary-general Ban Ki-moon for more time to speak: “You live in New York and I live in Syria,” he protested, “I have the right to give the Syrian version.”

The regime’s barrel bombs, chemical weapons and sieges extinguished moderate opposition, radicalising ever-more Islamist rebels and speeding the rise of Isis. Some half a million people have been killed. But Muallem used his international platform to continue to insist that the regime was fighting terrorism. He denied its chemical weapons use and propagated conspiracies that the civil rescue-group the White Helmets were terrorists.

A corpulent figure, Muallem appeared frail in his final public appearance, at a conference about refugee returns less than a week before he died.

Although he was a phone call away from Mr Assad, who sent wreaths of white flowers to his funeral, few judged he was part of the dictator’s tight-knit inner circle. But for embattled regime loyalists, Muallem, who is survived by his wife and three children, was nonetheless a figurehead.

Chloe Cornish