Yemeni government troops and Houthi rebels have been engaged in fierce battles in and around a coastal town seen as a major smuggling point for arms used to supply rebels.
In recent days, both sides have won and lost territory near the port of Mokha in what analysts and Yemen officials see as a make-or-break fight to sever a rebel supply line.
Saudi and U.S.-backed government forces are convinced that Houthis rely on Iranian smuggled arms coming through maritime ports along the western shores of Yemen.
"By taking Mokha, we deprive Houthis from the source where 40 to 50 percent of their smuggled arms are coming from," Ahmed Saif Al Yafei, a Yemeni army commander, told VOA.
Hard line on Iran
The Trump administration, which is taking a hard line against Iran, is keen on stopping the flow of weapons from Iranian ships to Houthi rebels.
The White House sees the Iranian supply line as supporting terrorism.
The New York Times reported last week that U.S. national security officials considered sending U.S. vessels to intercept an Iranian military ship in the Arabian Sea that they suspected of carrying an arms shipment. They backed off because of operational concerns, the newspaper said, at least for the time being.
"We are concerned about all of the weapons that are smuggled in," Michael Meyer, a U.S Central Command spokesman, wrote in an email to VOA. "Iran is supplying the Houthis with lethal aid - including advanced countermaritime capability - in contravention of U.N. Security Council resolutions."
U.S. Secretary of State Rex Tillerson on Thursday met on Yemen with counterparts from Britain, Saudi Arabia, the United Arab Emirates and Oman at a foreign ministers summit in Germany.
Iranian officials say they are not involved in supplying weapons to Houthis - despite credible evidence, Yemeni and U.S. officials say, that in recent months Iran has been violating a U.N. embargo prohibiting the transfer of arms to Houthis.
Mohsen Rezaei, Iran's Expediency Discernment Council secretary, said in early February that Houthis receive missiles and ammunition from Russia. Tehran's support to Houthis, he said, is limited to spiritual guidance and sympathy.
Battles waged for other ports
And Houthis say they already have weapons and that the U.S.-backed monitoring efforts on the Red Sea have virtually shut down weapons smuggling.
"We don't need to smuggle weapons. We defeat them and get theirs. We control several weapon stockpiles, too," said Aziz Hussein, the deputy spokesperson of the Houthi and Saleh forces.
The fight to control Mokha has intensified over the past couple of weeks. All warring factions are claiming victory in Mokha, including government forces loyal to President Abdu Rabu Mansour Hadi, Houthis and their ally of loyalists to former President Ali Abdullah Saleh.
Meanwhile, government forces claim full control over the Dhubab port on the southwestern coast of Yemen. Now they are aiming at reaching Hodeida port, one of the main and strategic harbors in the country.
Saudi-backed Yemeni officials say that since the beginning of the conflict two years ago, Houthis have continued to receive arms. Of 12 consignments of weapons that were aimed at reaching Houthis, the government seized five, officials say.
The last shipment seized by government forces was three months ago.
"There were around 100 pieces of anti-tank Kornet missiles in the last shipment we seized," Al Yafei said. "We have also seized 1,000 pieces of Kalashnikov and around a million bullets in the same shipment."
The Mokha port is 40 miles from Bab-el-Mandeb, the strategic strait on the Red Sea where millions of gallons of oil and refined petroleum products flow toward Europe, the United States and Asia every year.
To circumvent coalition surveillance, Houthi rebels have reportedly changed their tactics, resorting to more nimble boats.
"Houthis use small boats for sail to certain points inside the Red Sea in order to get their smuggled weapons from Iranian ships," said Ali Alkhulaqi, a Yemeni analyst who is close to the government forces.
Ultimately, though, the Houthis will continue their uprising even if they lose control of the coastline.
"They [Houthis] almost certainly receive some smuggled weapons, but these are not decisive in their ability to continue the war," said April Longley Alley, an analyst at International Crisis Group.
Source: Voice of America