BRUSSELS – Belgian police issued a new appeal on Monday for information about a man caught on CCTV at Brussels Airport with two others who are thought to have blown themselves up in the check-in area last Tuesday.

It was not clear whether the appeal meant the man, thought to have had a bomb with him, was on the run or that the police were simply trying to bolster their case that a suspect they have arrested and charged with “terrorist murder” is the man in the footage.

Half a dozen people have been charged in Belgium following Tuesday’s attacks on the airport and the metro. The death toll rose to 35 on Monday, excluding the two airport bombers and a third who blew himself up on a rush-hour train.

A Europe-wide hunt for suspects has revealed links with the network that attacked Paris last year and also foiled a new potential attack on France last week, officials said. But several suspects are reported to be still at large.

The man in a light jacket seen pushing a trolley with a suitcase on it in the airport video footage, which was released on Monday along with the appeal, has been dubbed “the man in the hat.”

He has been named by Belgian media as Faycal Cheffou, a self-styled freelance journalist.

A source close to the investigation, speaking on condition of anonymity, said a suspect named by prosecutors only as Faycal C who had been charged with attempted and actual terrorist murder, was believed to be Cheffou.

But the source repeated that there had been no official identification, implying police may be having difficulties linking him to the figure captured on CCTV, who was wearing glasses and whose hat was pulled down over his face.

The official police notice said they were seeking to formally identify the man, who is suspected of dumping his case containing a bomb, which did not go off, before running from the terminal.

Islamic State has claimed responsibility for both the Paris attacks and those in Brussels, which exposed weaknesses within intelligence services in Belgium, where some of the Paris attackers lived, as well as insufficient cooperation between security services across Europe.

Dutch anti-terrorism police arrested a 32-year-old suspect on Sunday in Rotterdam on France’s request and Italy arrested an Algerian on Saturday suspected of having forged documents for militants linked to the Brussels and Paris attacks.

Germany has also conducted raids but its Federal Criminal Police Office was among European security agencies still hunting for at least eight mostly French or Belgian suspects on the run in Syria or Europe, Die Welt am Sonntag newspaper said.

The U.S. State Department confirmed four U.S. citizens were among victims of nine different nationalities, including Belgian. More than 300 people were injured, many of them seriously.

Belgian Health Minister Maggie De Block said more of those wounded in the attacks had since died.

“Four patients died in hospital. Medical teams did everything possible. Total victims: 35,” she said in a tweet.

Other foreigners killed were British, Chinese, Dutch, French, German, Italian and Swedish.

The airport in Brussels remained closed on Monday and the metro was running a reduced service in the capital which was largely shuttered for the Easter holiday.

There was no sign of the nationalist protesters who clashed with police on Sunday at the Brussels bourse, where mourners have gathered and placed candles, wreaths and messages for victims.

The State Department has declined to name any of the four U.S. citizens killed, citing respect for their families.

Two of them were identified by relatives as Justin and Stephanie Shults, residents of Belgium originally from Tennessee and Kentucky who were last seen dropping off her mother at the Brussels airport before the explosion in the check-in area.

“The world lost two amazing people,” Justin Shults’ brother, Levi Sutton, said in a post on Twitter. “It’s not fair.”