Washington -- The security of Christians in Northern Iraq remains "tenuous" and will require close attention in the future, the State Department's religious freedom ambassador told members of Congress on Thursday.

While the situation is "far better in Northern Iraq right now" for Yazidis and Christians, who in 2016 were recognized by the State Department as genocide victims of ISIS in Iraq and Syria, there is still a lack of "true security in the area," Ambassador-at-Large for International Religious Freedom Sam Brownback said.

Ambassador Brownback testified on June 27 at the hearing of the Tom Lantos Human Rights Commission, chaired by Rep. Chris Smith (R-NJ), on "Violations of the International Right to Freedom of Religion" of Christians.

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The hearing was held two months after bombings in Sri Lanka on Easter Sunday killed more than 250 people, targeting churches and hotels.

A recent Pew Center study showed that Christians are persecuted in more countries around the world than any other religious group, in 144 countries.

"We stand for human dignity and respect for life of whomever is oppressed, and this Commission has and will continue to highlight the suffering of religious minorities around the globe, be they Ahmadi Muslims in Pakistan, Ba'hai in Iran, Buddhists in occupied Tibet, Yazidis in Iraq or the Muslim Rohingya people in Burma," Rep. Smith stated.

"Christians, however, remain the most persecuted religious group the world over, and thus deserve the special attention that today's hearing will give them," Smith said.

Smith noted that "sometimes there is an oversensitivity" in Western countries, and a hesitation to draw attention to the persecution of Christians elsewhere because of their own Christian majorities or large Christian populations. This is a "major, major mistake," he said on Thursday.

Security for Christians in Iraq is "still tenuous" right now, Brownback said on Thursday, and if another group like ISIS emerges to attack Christians and other religious minorities there they "need outside support to be there," he said.

Uncertainty among displaced Christians, and a lack of reliable support is leading to a "timidity" of genocide survivors to return home, he said, and the "longer that goes on," the greater the threat of Christians leaving the region for good.

Brownback also noted the efforts of countries like Poland and Hungary to work directly with local groups to assist Christians in the region.

Recovery of Christians in Sri Lanka from the deadly Easter bombings was another matter discussed at the hearing.

Asked by Rep. Ilhan Omar (D-Minnesota) about concerns by Catholics in Sri Lanka that the government is shutting down churches in the name of "security" after the bombings, Brownback said that the State Department has been pushing for Sri Lanka to protect the rights of religious minorities while recognizing security concerns.

Cardinal Malcolm Ranjith has done an "outstanding job" calling for peace and against retribution by Christians following the attacks, he said.

Brownback also previewed the State Department's upcoming Ministerial to Advance Religious Freedom in July, which he said he wished "to launch a grassroots movement globally" to promote religious freedom. He noted that a similar effort has been advanced to fight human trafficking for the last 20 years, and said it provided a template for success which could be followed.