WASHINGTON – President Barack Obama and Iraqi Prime Minister Nuri al-Maliki hailed the seeds of a growing cooperation between their nations, pledging that out of the fires of war would come a new friendship.

But they warned the path ahead could yet prove tough, with many obstacles to overcome and sectarian violence still threatening Iraq's stability.

"Both of us agree that the bonds forged between Americans and Iraqis in war can pave the way for progress that can be forged in peace," Obama pledged after White House talks with Maliki.

"America stands ready to help the Iraqi government build their capacity to provide basic services and to promote the rule of law."

It was their first White House meeting since Obama was elected in January, although the two men met in Baghdad in April.

It was also their first talks since US troops withdrew from Iraqi cities at the end of June, a milestone in Iraq's rehabilitation after the 2003 US-led invasion.

"Prime Minister Maliki and I are both deeply humbled by the sacrifices that have been made by Iraqis and Americans to create this opportunity," Obama said.

Violence had dropped markedly throughout the country in recent months, but attacks increased in the run-up to the US military pullback, with 437 Iraqis killed in June -- the highest death toll in 11 months.

Maliki, who on Thursday will visit the Arlington military cemetery to pay tribute to fallen US soldiers, said their talks "reflected the deep conviction on the part of both sides to establish a strategic friendship."

They had discussed ways "to activate the strategic relationship and the economic front, culture front, educational front, commercial front and in every possible area where the United States can play a role in supporting the Iraqi government," he added.

In a sign of the deadly unrest still plaguing Iraq, five Iranian pilgrims died Wednesday when their minibuses were ambushed near restive Baquba, a day after a wave of attacks across the country killed 24 Iraqis.

And Obama warned: "There are still those who want to foment sectarian conflict. But make no mistake, those efforts will fail."

Speaking through an interpreter, Maliki voiced confidence in the ability of his nation's forces, saying they had already shown their strength since US troops withdrew from Iraqi cities.

"Those who thought that the Iraqi forces, if the American forces can leave, will be incapable of imposing peace and security, these people proved to be wrong," he said.

Maliki has overseen a considerable transformation in his country since he took office three years ago, at a time of sprawling interfaith violence.

His authority has been boosted in past years, and he is hoping for US support in his bid to ease UN sanctions slapped on his country after Saddam Hussein's 1990 invasion of Kuwait.

Obama said Wednesday he stood ready to help Iraq in its campaign.

"I think would be a mistake for Iraq to continue to be burdened by the sins of a deposed dictator," he said, adding however that outstanding disputes between Iraq and some of its neighbors would first have to be resolved.

The Iraqi leader made his case at the United Nations earlier Wednesday in a private meeting with UN chief Ban Ki-moon, and later with envoys of the five permanent members of the UN Security Council -- Britain, China, France, Russia and the United States.

Maliki argued the sanctions were "no longer required" and said he was awaiting a report by Ban reviewing Iraq-related resolutions.

The sanctions require that Iraq satisfy Kuwaiti demands on reparations and the return of property, as well as demarcation of their shared border and the repatriation of the remains of prisoners of war.

Maliki is also set to meet during his four-day visit with Biden, Secretary of State Hillary Clinton, Treasury Secretary Timothy Geithner, Defense Secretary Robert Gates, and Democratic House Speaker Nancy Pelosi.

The Iraqi leader is hoping to drum up investment for a country in dire need of rebuilding after years of sanctions and war. His visit will include an investment conference at the US Department of Commerce.