WASHINGTON — President Barack Obama will attend a memorial service Tuesday honoring victims of the Fort Hood shootings, an attack he described as "all the more heartbreaking and all the more despicable" because it occurred on the nation's largest Army post.

He praised those who ended the shootings, which killed 13 and wounded 30 others, and lauded the armed services' diversity — a move designed to calm tensions about the suspected shooter, Maj. Nidal Malik Hasan.

"They are Americans of every race, faith and station. They are Christians and Muslims, Jews and Hindus and nonbelievers," Obama said in his radio and Internet address Saturday, airing the weekend before Veterans Day.

"They are descendants of immigrants and immigrants themselves. They reflect the diversity that makes this America. But what they share is a patriotism like no other."

After the address aired, Obama talked about the Fort Hood shootings with Democratic House members. On Capitol Hill for a private meeting on health care, Obama opened his remarks by speaking about Fort Hood, participants said.

He told lawmakers that the hardships members of the military make for the country "is what sacrifice really is," according to Rep. Robert Andrews, D-N.J., as opposed to "casting a vote that might lose an election for you."

The president asked for patience while officials piece together what happened Thursday in Texas.

"We cannot fully know what leads a man to do such a thing," Obama said in his address. "But what we do know is that our thoughts are with every one of the men and women who were injured at Fort Hood. Our thoughts are with all the families who've lost a loved one in this national tragedy."

But Obama said while "we saw the worst of human nature on full display, we also saw the best of America."

"We saw soldiers and civilians alike rushing to aid fallen comrades, tearing off bullet-riddled clothes to treat the injured, using blouses as tourniquets, taking down the shooter even as they bore wounds themselves," Obama said.

"We saw soldiers bringing to bear on our own soil the skills they had been trained to use abroad — skills that been honed through years of determined effort for one purpose and one purpose only: to protect and defend the United States of America."

The White House had said Obama would attend a service, but awaited the families' decision about the schedule. White House officials insisted they would not dictate a date.

Obama was scheduled to arrive in Asia on Thursday, but a source familiar with Obama's planning said Saturday that Obama would arrive in Tokyo — his first stop on the schedule — a day later than expected. The source spoke on the condition of anonymity because the White House plans to release a revised schedule in the coming days to reflect Obama's plans to travel to Texas.

Obama on Friday ordered the flags at the White House and other federal buildings to be at half-staff until Veterans Day, on Wednesday.

"It is an act of violence that would have been heartbreaking had it occurred anyplace in America. It is a crime that would have horrified us had its victims been Americans of any background," Obama said during his address, recorded Friday and released early Saturday.

"But it's all the more heartbreaking and all the more despicable because of the place where it occurred and the patriots who were its victims."