Forces loyal to the Saudi-led coalition fighting Houthi rebels advanced on Monday to within 5 kilometers (3 miles) of the port facilities in Yemen's contested Red Sea city of Hodeida, the current epicenter of the civil war, officials said.

Coalition aircraft and naval forces continue to pound rebel positions, and fighting has killed dozens of combatants from both sides, with dozens of military vehicles destroyed or burning along the front lines, they added.

Associated Press footage shows coalition forces on the main road to the capital, Sanaa, cutting off the highway and further encircling the rebels.

The officials, speaking on condition of anonymity because they are not authorized to brief reporters, say other offensives have been launched elsewhere, including in the Dhale and Hajjah provinces. Fierce fighting also erupted a day earlier in the provinces of Bayda, to the south, and Saada, a Houthi stronghold in the north. They say a total of 580 people have been killed or wounded in Yemen since the coalition offensive began four days ago, without giving a breakdown.

The offensive came despite recent calls by the Trump administration for a cease-fire by late November.

The Saudi-led and U.S.-backed coalition has been at war with the Iran-aligned rebels since March 2015 in a stalemated conflict that has generated the world's worst humanitarian crisis. The U.S. has sold billions of dollars' worth of arms to Saudi Arabia and provides logistical and other support to the coalition.

The rebels say they have killed and wounded dozens of coalition troops, but did not provide a breakdown.

Both sides have reported several civilians killed in the latest fighting.

Save the Children's Yemen director, Tamer Kirolos, said the latest escalation could put tens of thousands of children in the line of fire around Hodeida and block essential aid deliveries. An estimated 70 percent of Yemen's food and humanitarian aid enters through Hodeida.

"The international community must increase diplomatic pressure and intensify efforts to secure an immediate halt to the offensive and a comprehensive ceasefire," he said in a statement, urging both sides to stop the fighting.