As Yemen's Houthi rebels continue to target ships in a Mideast waterway, satellite pictures analyzed by The Associated Press show what appears to be a new airstrip being built at an entrance to that crucial maritime route.

No country has publicly claimed the construction taking place on Abd al-Kuri Island, a stretch of land rising out of the Indian Ocean near the mouth of the Gulf of Aden. However, satellite images shot for the AP appear to show workers have spelled out "I LOVE UAE" with piles of dirt next to the runway, using an abbreviation for the United Arab Emirates.

Both the Gulf of Aden and the Red Sea to which it leads have become a battleground between the Houthis and U.S.-led forces in the region as Israel's war on Hamas in the Gaza Strip rages - potentially allowing a nation to project its power into the area.

The construction comes as the presence of troops from the Emirates in the Socotra island chain to which Abd al-Kuri belongs - and that of the separatist force it backs in southern Yemen - have sparked clashes in the past.

In response to questions from the AP, the United Arab Emirates said Thursday that "any presence of the UAE on Socotra island is based on humanitarian grounds that is carried out in cooperation with the Yemeni government and local authorities."

"The UAE remains steadfast in its commitment to all international endeavors aimed at facilitating the resumption of the Yemeni political process, thereby advancing the security, stability, and prosperity sought by the Yemeni populace," it added, without elaborating.

The Yemeni Embassy in Washington and Saudi Arabia, which leads a coalition fighting the Houthis, did not respond to questions.

Abd al-Kuri is about 35 kilometers (21.75 miles) in length and about 5 kilometers (3.11 miles) at its widest point. It sits closer to the Horn of Africa than it does to Yemen, the Arab world's poorest nation, which has been at war for years.

Along that widest point sits the airstrip construction. Satellite photos from Planet Labs PBC analyzed by the AP showed trucks and other vehicles grading the runway on March 11, turning part of its sandy features a dark brown. Planet Labs images of the site shot for the AP on Monday, Tuesday and Wednesday showed vehicles in different positions and active work being done there, possibly including paving the site.

The runway, running north to south, measures some 3 kilometers (1.86 miles). A runway of that length can accommodate attack, surveillance and transport aircraft, even some of the heaviest bombers.

Construction initially could be seen in the area in January 2022, with a diagonal, shorter runway being carved out of the sand, according to Planet Labs imagery. The first signs of construction of the longer north-south runway were in July 2022, but work later halted.

This month, there's been increased activity on Abd al-Kuri, including construction at the northern edge of the runway, close to the water, and the movement of heavy vehicles.

That works corresponds with a report last week by Abu Dhabi's state-linked broadcaster Sky News Arabia, which claimed to quote an anonymous U.S. defense official as saying America had "strengthened our missile defenses on Socotra Island" in anticipation of the rebels attacking U.S. bases. Socotra is the main island of the Socotra chain, about 130 kilometers (80 miles) from Abd al-Kuri.

The U.S. military told the AP it is not involved in the construction on Abd al-Kuri, nor is there any American "military presence" elsewhere in Yemen. U.S. special forces have launched raids in the past in Yemen, while a two-decade American drone strike campaign has targeted the country's local al-Qaida affiliate.

There also weren't any air defense batteries immediately discernible around the Abd al-Kuri Island site in satellite imagery. However, what appear to be piles of dirt at the site had been arranged to spell "I LOVE UAE" just east of the runway.

The island of Socotra, a UNESCO World Heritage site home to the rare Dragon Blood tree, has long been a strategic port given its location on a key East-West trade route for cargo and energy shipments coming from Asia and the Middle East onward to Europe. The Soviet Union once used Socotra as an anchorage for both its surface fleet and submarines when South Yemen, a Communist nation based in Aden, ruled the island from 1967 until 1990.

The island since has felt far removed from the chaos that has gripped Yemen in the decades since, from unification, to civil war, to the Iranian-backed Houthi rebels' sweeping entrance into the capital in 2014. A Saudi-led coalition that includes the UAE entered the Yemen war in 2015 on behalf of the country's exiled government and has been caught in a grinding, nearly decadelong conflict since.

In 2018, the UAE deployed troops to Socotra Island, sparking a dispute with Yemen's exiled government. Two years later, clashes broke out between Yemeni separatists backed by the UAE and other forces there.

Meanwhile, Iranian-linked media and the Houthis have alleged without providing evidence that the Emiratis allowed Israel to operate from Socotra as well. Israel has not acknowledged any presence there, and the Israeli prime minister's office declined to comment.

Since November, the Houthis have attacked ships, saying they want to force Israel to end its offensive in the Gaza Strip against Hamas. The ships targeted by the rebels, however, largely have had little or no connection to Israel, the U.S. or other nations involved in the war. The rebels also have fired missiles toward Israel, though they have largely fallen short or been intercepted.

While President Joe Biden entered office in 2021, he pulled support from the Saudi-led coalition, declaring: "This war has to end." But in January, the U.S. began launching airstrikes targeting the Houthis over their attacks on shipping, a near-daily campaign of attacks that continues today.

The airfield on Abd el-Kuri isn't the first mysterious airstrip to begin construction amid Yemen's war. In 2021, the AP reported that an airfield was being built on Mayun Island, also known as Perim Island, which sits in the narrow Bab el-Mandeb Strait linking the Gulf of Aden to the Red Sea.

Then, military officials with Yemen's internationally recognized government, which the Saudi-led coalition has backed since 2015, said the UAE was building the runway. The Saudi-led coalition battling the Houthis later acknowledged having "equipment" on the island, while a militia leader and nephew of Yemen's late strongman president Ali Abdullah Saleh acknowledged that his Emirati-backed troops were stationed there.

From The Associated Press