GORI, Georgia — Russia took its first steps deep into Georgian territory yesterday while the president of its beleaguered neighbor made an international plea for help, saying the world had a “moral duty to stop this madness.”

Russia’s opening of a second front yesterday afternoon saw it capture the town of Senaki, 20 miles inside Georgia. The move cut the country in two by seizing a key road and rail junction.

The operation, which involved some 300 Russian troops, marked the moment the ground war spread beyond the boundaries of the semi-autonomous regions of South Ossetia and Abkhazia.

That, and the retreat of Georgia’s heavily outnumbered forces from the central city of Gori, underlined the ease with which Russia has so far been able to act against its tiny neighbor, incurring nothing but harsh words from the West.

President Saakashvili of Georgia accused Russia of the “invasion, occupation, and annihilation of an independent democratic country.” He urged the international community to act against what he called the “pre-planned, cold-blooded, and pre-meditated murder of a small country.”

President Bush, criticized Russia’s “disproportionate” actions and said Georgia’s “sovereignty must be respected.”

The French foreign minister, Bernard Kouchner, arrived in Georgia and visited Gori, areas of which have been heavily bombed. “We are here to stop this bloody war,” he said.

President Sarkozy of France, the holder of the European Union’s rotating presidency, is expected to visit Georgia today and then fly on to Moscow to urge a truce.

Prime Minister Brown said there was “no justification for continued Russian military action in Georgia, which risks a humanitarian catastrophe.”

He added: “The Georgian government has offered a ceasefire, which I urge the Russians to reciprocate without delay.”

Georgia declared a unilateral ceasefire on Sunday and withdrew its forces from South Ossetia, where the fighting began last week. It left the enclave firmly in the Kremlin’s grasp.