Somalia’s beleaguered transitional government received desperately needed support on Thursday as Secretary of State Hillary Rodham Clinton praised its president as “the best hope we’ve had for some time,” then strongly warned Eritrea to stop supporting insurgents in the country.

Mrs. Clinton met with Sheik Sharif Sheik Ahmed, elected Somalia’s president in January, for more than an hour. She promised more aid, training and equipment, in addition to the millions of dollars’ worth of weapons the United States has recently shipped to his government.

“We need to be there to help them deliver the results of stability to the people of Somalia, who have suffered for so long,” Mrs. Clinton said.

Sheik Sharif can use the help. His moderate Islamist government controls no more than a few city blocks in a country the size of Texas, with extremist Islamist groups, like the Shabab, in charge of much of the rest.

Mrs. Clinton said the battle for Somalia, which has been the lawless home to Islamist extremists, terrorists, gun runners, drug smugglers, teenage gunmen and even modern-day pirates for the past 18 years, is deeply connected to American interests.