Adama Barrow has been sworn in as Gambian president in Senegal's capital, Dakar, after weeks of political impasse. Senegalese troops charged into neighboring Gambia late Thursday in a show of force to oust longtime ruler Yahya Jammeh after he failed to step aside when his mandate ended at midnight after losing the presidential election last month. The troops moved in shortly after Adama Barrow was inaugurated as Gambia's first new leader in more than 22 years at the country's embassy in neighboring Senegal after a final effort at diplomatic talks with Jammeh failed to secure his departure. Senegalese military spokesman Col. Abdou Ndiaye confirmed to The Associated Press that the first West African troops had crossed into Gambia and were on their way to the capital, Banjul. AP journalists saw at least 20 military vehicles gathered at the border town of Karang. In his inaugural speech, which took place under heavy security, Barrow called on Jammeh to respect the will of the people and step aside. The new president also called on Gambia's armed forces to remain in their barracks as the regional military intervention got underway. Outside Gambia's embassy in Dakar, Baal Jaabang held up a freshly framed portrait of Barrow, already printed with the words: "His Excellency Adama Barrow, President of the Republic of Gambia." "I'm extremely delighted, so wonderfully happy today," he said. "But now the situation risks moving into fighting. No Gambian â€" in the diaspora or back home â€" wants our country to face fighting." Barrow had come to Senegal last week at the urging of West African mediators, who had feared for his safety amid the political crisis. He arrived at the embassy to cheers of joy from hundreds of Gambians who had gathered, with national flags, for a glimpse of the new president. "Our national flag will now fly high among the most democratic nations of the world," Barrow said after the ceremony. Barrow was declared the winner of the Dec. 1 election and at first was congratulated by Jammeh in a phone call aired on state television. But once it was suggested that Jammeh could face criminal charges linked to his long rule, he backtracked and challenged the vote in court, alleging irregularities. Jammeh on Thursday remained at his official residence and intended to stay there, said an official close to the administration who was not authorized to speak to reporters. If the regional force is going to arrest Jammeh, it will have to be there, the official said. Many of Jammeh's loyalists will resist, the official added.