The United Nations Security Council passed a unanimous resolution on Monday, demanding access to the crash site of downed Malaysia Airlines Flight MH17 in Ukraine. (Reuters)

Four days after the shoot-down of a Malaysian airliner, the world remained uncertain and divided on how to respond while awaiting conclusive evidence to go along with allegations that separatists in eastern Ukraine, and their Russian backers, were responsible.

A U.N. Security Council resolution, which passed unanimously Monday, demanded that international inspectors be given immediate, full access to the crash site and that “those responsible for this incident be held to account.”

At the White House, President Obama said that “the burden is now on Russia” to rein in separatists impeding investigation of the crash and that “costs for Russia’s behavior will only continue to increase” if it continues backing the armed groups.

President Vladi­mir Putin continued to promise full support for an international investigation, even as Russian military leaders contested claims by U.S. officials that Russian forces provided the separatists with a sophisticated antiaircraft system of the type used to shoot down the plane and trained them in how to use it.

Speaking on Russian television, Lt. Gen. Andrei Kartopolov, head of the main operations directorate of the Russian Armed Forces General Staff, denied that Russia had supplied the weapon. He produced several photographs, including one allegedly taken on Thursday, which he said showed a Ukrainian military Buk antiaircraft battery in the vicinity of the crash and said that Ukrainian-released photographs of the area were faked.

Satellite image of the debris field near Hrabove

Kartopolov demanded the release of U.S. satellite images of the area at the time of the crash. He also claimed that a Ukrainian government fighter jet was in the air within two or three miles of the ill-fated jetliner, implying that it might have been involved in the shoot-down.

Although Obama did not mention any new sanctions against Russia, European Union foreign ministers will meet in Brussels on Tuesday to consider additional asset freezes and the designation of some unspecified Russian companies.

Those in favor of such measures, led by Britain with increasing support from Germany, have hardened considerably since the plane was downed. But some E.U. members still oppose sanctions against Russian businesses akin to those Obama announced last week.

In addition to economic concerns, a European diplomat said, there is also worry that pushing Russia now, before the crash site and the bodies of all 298 victims are secured, may make the difficult situation on the ground in Ukraine even harder.

That concern was apparent in the wording of the U.N. resolution. In a compromise designed to secure Moscow’s vote within the 15-member Security Council, the resolution referred only to “armed groups” in Ukraine and did not mention Russia or the separatists.

The vote came as a handful of Dutch investigators were allowed access to the site, in separatist-controlled eastern Ukraine, and a train carrying the bodies of most of the victims left for the Ukrainian city of Kharkiv. Two-thirds of the dead were from the Netherlands, where the Amsterdam-to-Kuala Lumpur flight originated.

“There are different reasons” that some Europeans are likely to have a more “conservative approach” toward expanded sanctions now, said the European diplomat, who spoke on the condition of anonymity in advance of the meeting. While most are worried about the impact on their own economies, the Dutch are focused on the bodies of the victims.

“They want to reunite those who lost lives and won’t do anything that risks” that objective, the diplomat said.

Dutch Foreign Minister Frans Timmermans, who traveled to New York to speak at the council session, charged that “a political game . . . has been played with human remains, and it is despicable.”

“Since Thursday, I’ve been thinking,” Timmermans said. “How horrible must have been the final moments of their lives when they knew the plane was going down. Did they lock hands with their loved ones? Did they hold their children close to their hearts? Did they look each other in the eyes one final time in a wordless goodbye? We will never know.”

Nearly all of those who spoke during the Security Council session confined their remarks to the terms of the resolution itself, although the United States and Russia exchanged some caustic words.

“There is one party from which we have heard too little condemnation” of the downed plane, U.S. Ambassador Samantha Power said, “and that is Russia. . . . If Russia is not part of the solution, it will continue to be part of the problem.”

Russia’s U.N. ambassador, Vitaly Churkin, said that his government “stands ready to provide any assistance necessary in organizing and conducting an impartial international investigation. . . . Perhaps Washington does not know about those efforts,” he said. “If that’s the fact, perhaps the U.S. Embassy should be better informed.”

At the same time, Churkin charged, Ukrainian government forces were attempting to use the “shock of the international community” over the shoot-down to step up their military operations against the separatists elsewhere in the eastern part of the country, where “indiscriminate artillery and airstrikes are hitting cities and killing civilians.”

British Prime Minister David Cameron on Monday openly criticized other European nations’ reluctance to get even tougher on Russia, emphasizing that additional economic measures against Moscow were justified by its responsibility for the overall conflict in Ukraine, beyond the events of last week.

“Those of us in Europe should not need to be reminded of the consequences of turning a blind eye when big countries bully smaller countries,” Cameron told the British Parliament.

“It is time to make our power, influence and resources felt,” he said.

Cameron said that German Chancellor Angela Merkel and French President François Hollande agreed with him on the need to “push our partners in the European Union to consider a new range of hard-hitting sanctions against Russia.”

“Phase 3” sanctions against major sectors of the Russian economy remain thorny in Europe, in part because the region is divided over what they would look like.

Whatever they decide about sanctions, leading diplomats in Europe were clearly not buying Russian denials of responsibility for the downing of the Malaysian airliner. “There are those who remember the press conference where the Soviet Ministry of Defense denied everything concerning the shooting down of KAL 007,” said Carl Bildt, Sweden’s foreign minister. The Soviet Union eventually acknowledged the 1983 shoot-down of a Korean Air Lines flight over the Sea of Japan, which killed all 269 passengers and crew members, and charged that the plane was on a spying mission.

Dutch Prime Minister Mark Rutte vowed that “if access remains insufficient in the coming days, all political, economic and financial measures are on the table for those that are directly or indirectly responsible for this.”

Some observers were skeptical about whether the Europeans would move rapidly toward the strictest possible sanctions on Russia. Henning Riecke, a security expert from the German Council on Foreign Relations in Berlin, said “the question of who is responsible for the crash of the Malaysia Airlines plane has not been completely been resolved yet; I don’t think there will be sanctions like the ones imposed by the U.S.”

“The price for sanctions targeting entire industries would be too high for Europe and for the Germans,” he said.

Faiola reported from Berlin. Karla Adam in London and Stephanie Kirchner in Berlin contributed to this report.