Turkish police on Tuesday raided the offices of an al Qaeda-linked charity group responsible for organizing the 2010 Gaza flotilla that caused a deadly international incident.

The main offices of the Humanitarian Relief Foundation (IHH), a Turkish charity that claims to support humanitarian causes, were raided by Turkish anti-terror forces in connection with a larger bust on al Qaeda militants, according to Turkish media reports.

IHH has long been suspected of having ties to terror organizations, including Hamas and al Qaeda.

Regional experts said the Turkish raid provides the first definitive evidence that IHH is not the humanitarian organization it claims to be.

"One gets a sense that the Turkish military knows something about the IHH that we’ve long suspected," said Jonathan Schanzer, a former intelligence analyst who has written about U.S. government bids to designate the IHH a terror group.

IHH, which is often lauded by U.S. groups critical of Israel, has been encircled in controversy since it organized the 2010 Gaza flotilla, a supposedly humanitarian aid mission that sought to breach Israel’s blockade of the Gaza Strip.

IHH claimed that it was carrying peaceful pro-Palestinian activists aboard its ship. However, when Israeli Navy personnel boarded the flotilla, activists attacked the soldiers with guns, knives, crowbars, and other weapons.

Two Israeli commandos were severely wounded during the attack, while 10 of the activists died as a result of the violence.

Anti-Israel critics such as the Center for American Progress’s (CAP) Matt Duss and others lashed out at the Israeli military and defended IHH as a peaceful humanitarian group.

Tuesday’s raid, however, paints IHH in a different light.

Turkish police searched an IHH storage facility located near the Syrian border where the group has been suspected of smuggling arms, according to reports.

Less than two weeks before Tuesday’s raid, Turkish police stopped a truck "laden with weapons" on the Syrian border. Under questioning, the driver claimed he was carrying "aid on behalf" of IHH, according to al Arabiya.

IHH continues to maintain that it is not tied to any terror groups despite the mounting body of evidence.

"The operation was aimed at preventing the İHH from sending humanitarian aid to Syria," the group claimed in a statement, Turkey’s Hurriyet Daily News reported.

"They are trying to show the İHH as if it is related to terror organizations," the group maintained.

U.S. lawmakers and others have long pushed the U.S. government to declare IHH a supporter of terrorism.

Reps. Howard Berman (D-Calif.) and Ed Royce (R-Calif.) urged the U.S. Treasury Department in 2010 to designate IHH for its terror links.

"It is puzzling that IHH has not already been designated," the Foundation for Defense of Democracy’s (FDD) Schanzer wrote in 2010. "The group advertises the fact that it is a participating member of the Saudi-based umbrella organization Union of Good (Ittilaf al-Kheir in Arabic). On Nov. 12, 2008, Treasury listed the Union as a terrorist entity, stating that the group was ‘created by Hamas leadership to transfer funds to the terrorist organization.’"

The IHH has been tied to the top terrorists in these organizations and further accused of playing a key role in terror attacks.

"French magistrate Jean-Louis Brougière testified in 2001 that IHH had an ‘important role’ in Ahmed Ressam's failed ‘millennium plot’ to bomb the Los Angeles airport in late 1999," according to Schanzer. "Brougiere added that the Turkish IHH was ‘basically helping al Qaeda when [Osama] bin Laden started to want to target U.S. soil.’"

Germany additionally banned IHH in 2010, while the Israelis banned it in 2002 and then again in 2008.

Schanzer told the Washington Free Beacon in an interview that IHH’s ties to terror have become clearer over the years.

"There are these ties that have been hard to ignore and they come up one after the next," he said.