RIYADH, Saudi Arabia - From the heart of Europe to the expanse of Saudi Arabia's desert, President Barack Obama's weeklong overseas trip amounted to a reassurance tour for stalwart, but sometimes skeptical, American allies.

At a time when Obama is grappling with crises and conflict in both Europe and the Middle East, the four-country swing also served as a reminder that even those longtime partners still need some personal attention from the president.

Europe is a crucial linchpin in Obama's efforts to rally the international community in opposition to Russia's incursion in Ukraine, but the continent's leaders have concerns about the impact tougher Western sanctions on Moscow could have on their own economy. Saudi Arabia has a hand in nearly every Middle East crisis consuming White House attention, including the Syrian civil war, nuclear negotiations with Iran and peace talks between the Israelis and Palestinians, but has grown anxious about Obama's positioning in the region.

Obama departed for Washington on Saturday with much left unresolved on each of those matters. Still, officials said the president had made progress during his pilgrimage to Saudi King Abdullah's desert oasis, as well as in his hours of conversations with European leaders. The president's advisers were particularly bullish about his meeting in the Netherlands with allies from the Group of Seven leading industrial nations, which agreed to indefinitely suspend Russia from the larger Group of Eight.

"There's been a lot of movement in the last several days that suggest that Europe has been stirred to action by the events in Ukraine, and I think the president felt a degree of unity in that G7 meeting, in the EU session at NATO, and then with the individual leaders that he met with," said Ben Rhodes, Obama's deputy national security adviser.

Obama's stops in the Netherlands and Belgium were scheduled long before Russia's provocations in Ukraine but ended up being a well-timed opportunity for the president to discuss the crisis personally with Europe's leaders. As Obama sought pledges that Europe would cooperate if tougher economic sanctions on Russia become necessary, he also recommitted American support for NATO, the trans-Atlantic military alliance.

Those personal assurances from the president were welcomed by a continent that has developed something of an inferiority complex while watching Obama curry favor with Asia and get consumed by Mideast crises. Though Obama remains popular with the European public, he has also irked some leaders with what they've seen as slights to the European Union, the often unwieldy 28-nation bloc.

A particular sticking point for Europe was the fact that Obama had never visited Brussels, the headquarters city of both the EU and NATO. Obama finally checked that box on this latest trip, using his stop in the Belgian city to deliver a speech urging Europe to take a leadership role in protecting Ukraine's sovereignty against Russian provocations.

"The policies of your government, the principles of your European Union, will make a critical difference in whether or not the international order that so many generations before you have strived to create continues to move forward, or whether it retreats," he said, standing before a crowd of young people at the Palais des Beaux-Arts museum.

After stopping in Rome for a highly anticipated meeting with Pope Francis, Obama headed to Saudi Arabia for a visit with the kingdom's aging monarch. Despite the decades-long alliance between the U.S. and the oil-rich Gulf nation, Saudi's royal family has grown skeptical of the president's positioning in the region during a period of rapid and unpredictable change in the Arab world.