The first C-17 plane carrying humanitarian supplies arrived Wednesday in Tbilisi, Georgia, White House Press Secretary Dana Perino said. Another is scheduled to arrive on Thursday with additional supplies.
Also Wednesday, President Bush said he is skeptical that Moscow is honoring a cease-fire in neighboring Georgia, demanding that Russia end military activities in the former Soviet republic and withdraw its forces.
Bush, who pushed back his upcoming vacation to monitor the situation in Georgia, said Russia must ensure that "all lines of communication and transport, including seaports, roads and airports," remain open to deliveries and civilians.
"The United States stands with the democratically elected government of Georgia and insists that the sovereignty and territorial integrity of Georgia be respected," Bush said during brief but stern remarks in the White House Rose Garden.
Moscow's apparent violation of a cease-fire in neighboring Georgia puts its global aspirations at risk, he said.
Secretary of State Condoleezza Rice will travel to France and Tbilisi to mediate the growing crisis between the two countries. The visit follows a meeting between French President Nicolas Sarkozy and Russian President Dmitry Medvedev that outlined a six-point plan to end the fighting in Georgia, which has displaced 100,000 people and battered the country's landscape.
France plans to ask the U.N. Security Council to approve the plan by the end of the week, diplomats said.
Medvedev said Russia was halting military action because Georgia had paid enough for its attack last Thursday on South Ossetia. "But now Russia has now pushed this well beyond" the South Ossetian conflict, Rice said.
During Rice's last visit to Tbilisi, she warned Georgian President Mikhail Saakashvili not to get into a military conflict with Russia, The New York Times reported on Wednesday.
Saakashvili said Bush's remarks mean Georgian ports and airports will be placed under U.S. military control, Reuters reported. The Pentagon denied the report.
Bush's comments came amid confusion and fears Russian military vehicles could be moving deeper into Georgian territory. Georgian officials said the city of Gori was looted and bombed by Russian troops. An AP reporter later saw dozens of armored vehicles leaving the city, roaring south.
Moscow denied the claim, but it appeared to be on a technicality; a BBC reporter in Gori reported that Russian tanks were in the streets as their South Ossetian separatist allies seized Georgian cars and looted and set fire to Georgian homes.
"Russia has also stated that it has halted military operations and has agreed to a provisional cease-fire," Bush said. "Unfortunately, we've been receiving reports of Russia[n] actions that are inconsistent with these statements."
A FOX News correspondent in Gori said he received a text message from other reporters warning his crew to "get out now." On their way out, they witnessed more than 50 Russian armored vehicles on the road into Gori.
A Sky News crew was robbed of its vehicle and equipment by gunmen believed to be Ossetians.
To the west, Russian-backed Abkhazian separatists pushed Georgian troops out of Abkhazia and even moved into Georgian territory itself, defiantly planting a flag over the Inguri River and laughing that retreating Georgians had received "American training in running away."
A Russian government official who was not authorized to give his name said that Russian troops had checked a Georgian military base near Gori and found a large amount of abandoned weapons and ammunition. Russian troops moved to take the supplies to a safe place as part of efforts to demilitarize the area.
Saakashvili said the United States and the West have underestimated Russia's regional ambitions, saying Georgia warned the West that a large-scale Russian invasion was coming but were told by the U.S. State Department that the Russians "are not going to do that."
FOX News' Steve Harrigan and The Associated Press contributed to this report.