NEW YORK — One by one, the names of the injured, dead, and missing are emerging.

Faced with spotty cellular reception, language barriers, time zone differences, and travel restrictions, relatives and friends of those caught in the firestorm of terrorist attacks Tuesday in Brussels have taken to posting pictures and pleas for information and prayers on Facebook and other sites.

“Pray for my best friend and her brother that were at the Brussels airport during the attacks,’’ Alexa Eskinazi wrote on Facebook on Tuesday. “We still have not heard any news.’’

At least 31 people died and about 300 were injured in the bombings.

The authorities have asked for patience in figuring out the identities of the victims, a process slowed in part, they say, because of the condition of some of the bodies. And since the attacks were launched in the de facto capital of the European Union and the home of NATO’s headquarters, more than the usual language and cultural barriers are expected. Victims from as many as 40 nationalities were caught up in the attacks, according to Didier Reynders, Belgium’s foreign minister.

In the hours after the attacks, names began to trickle out on Twitter and Facebook as pockets of social media became virtual bulletin boards for people desperate for information on their loved ones. In one Facebook group, called Bruxelles-profil Recherche Famille, messages spilled in every few minutes on Wednesday.

Among the dozens thought to be missing is Raghavendran Ganesan, who was thought to have been commuting at the time of the explosion, according to a Facebook post by his sister on Tuesday. Ila Yadav, who works at Infosys Technologies Ltd., an information technology company, posted to a missing persons Facebook group to say that Ganesan is her colleague.

David Dixon, a British national living in Brussels, normally took the subway to work and is also missing, according to the BBC. Dixon works as a contractor for Euroclear, a financial services company.

“We are in touch with his partner and continue to coordinate with the authorities in locating David,’’ Tristan Peniston-Bird, a Euroclear spokesperson, said in an e-mail Wednesday. “Our primary concern is the safety and protection of our people, and our thoughts go out to those affected by yesterday’s attacks.’’

On Facebook, family and friends, including Eskinazi, have posted several notices about Alex Pinczowski and Sascha Pinczowski, siblings who were believed to have arrived at the airport on Tuesday. Both listed New York as home on Facebook. Pinczowski’s Facebook page says that she is originally from Greece.

Stephanie and Justin Shults, an American couple living in Brussels, were thought to be missing after dropping Shults’s mother off at the airport to catch a flight home, according to a CBS affiliate in Lexington, Ky., where Shults is from.

Shults’s employer, Mars Inc., said Wednesday that the couple was still missing.

Mark Toner, a deputy spokesman for the State Department, said that about a dozen Americans were wounded in the attacks, but that the department was not aware of any Americans who had been killed.

“We must emphasize that a number of US citizens remain unaccounted for and the Kingdom of Belgium has not yet released nationality information for reported fatalities,’’ he continued. “Our own internal US government accountability is ongoing, and we are making every effort to account for the welfare of both Chief of Mission personnel and US citizens in the city.’’

Other Americans thought to be present at the time of the attacks included a member of the Air Force and four members of his family; one Navy service member, one French-American with dual nationality; and three missionaries.

On Facebook and Twitter, people have also been asking for information on the whereabouts of three other people, Sabrina Fazal, Janina Panasewicz, and Patricia Rizzo. Little detail is known about them.

In other cases, deaths were confirmed online. On Wednesday morning, the Université Saint-Louis in Brussels announced the death of a Belgian student, Leopold Hecht.

“There are no words to describe our dismay in the face of this news,’’ Pierre Jadoul, rector of the school, wrote on Facebook in French. “All our thoughts go out to his family and loved ones.’’

On Tuesday, Fernando Tapia Coral confirmed the death of his sister, Adelma Tapia Ruiz, 36, a mother of 3-year-old twin girls from Peru, on Facebook. Ruiz was traveling home when the bombs went off at Brussels Airport. Her husband and one of her daughters were hospitalized after the attacks. Friends and relatives are still in shock.

“At first I thought it was someone else,’’ a friend, Lady Sindey Jouany, said, “and it took time to understand how this could have happened to her and how close to home it has hit.’’