By Nathan Layne

GRAPEVINE, Texas, March 28 (Reuters) - When former Congressman Matt Gaetz opened his speech by aligning with a Republican faction "loyal to only one nation," his message to the Conservative Political Action Conference was clear: It was a veiled swipe at perceived Israeli influence over U.S. politicians, even without naming Israel outright.

KYIV, March 28 (Reuters) - Ukraine's President Volodymyr Zelenskiy said on Saturday he had met with United Arab Emirates President Sheikh Mohammed bin Zayed Al Nahyan and that they had agreed to cooperate in the field of security and defence.

"Our teams will finalise the details," Zelenskiy said on the Telegram app.

The two leaders tackled opportunities to advance bilateral cooperation under the Comprehensive Economic Agreement between the two sides, the Emirati state news agency WAM said, without further elaborating.

The Israeli military said it had struck an Iranian research facility for naval weapons, while a series of loud explosions rattled Tehran as night fell on Saturday.

The fresh attacks on the capital came after Yemen's Houthi rebels announced their entry into the Middle East war by launching a missile towards Israel.

The intervention of Iran's Yemeni allies is sure to spark concern about disruptions to Red Sea shipping, which would only compound the widening economic fallout from the effective closure of the vital Strait of Hormuz off Iran.

ISLAMABAD, March 28 (Reuters) - Iranian President Masoud Pezeshkian has told Pakistan's Prime Minister Shehbaz Sharif that trust is needed to facilitate talks and mediation on the conflict in the Middle East, the prime minister's office said on Saturday.

It said Pezeshkian had praised Pakistan's diplomatic efforts and that the two leaders had discussed hostilities in the region and efforts to end the conflict during a call that lasted over an hour. Sharif briefed Pezeshkian on Pakistan's diplomatic contacts with the United States and Gulf states, it said.

ISLAMABAD/ ISTANBUL, March 28 (Reuters) - Pakistan will host Saudi Arabia, Turkey and Egypt for talks from Sunday on the Iran war as Islamabad positions itself as a potential venue for U.S.-Iran negotiations on the month-old conflict.

The four countries' foreign ministers will hold "in-depth discussions on a range of issues, including efforts to de-escalate tensions in the region" during the two-day talks, Pakistan's foreign ministry said in a statement on Saturday.

Here are the latest developments in the Middle East war:

- Ukraine-Qatar deal -

Qatar and Ukraine signed a defence agreement including cooperation on countering threats from missiles and drones, the Gulf state's defence ministry said, as Iran pressed an aerial campaign against its neighbours.

"The agreement includes collaboration in technological fields, development of joint investments and the exchange of expertise in countering missiles and unmanned aerial systems," the ministry said in a statement during a visit to Qatar by Ukrainian President Volodymyr Zelensky.

Qatar and Ukraine signed a defence agreement on Saturday that included cooperation on countering threats from missiles and drones, the Gulf state's government said, as Iran presses an aerial campaign against its neighbours.

Earlier on Saturday, Ukrainian President Volodymyr Zelensky -- during a previously unannounced flurry of visits to Gulf nations -- said his country and the United Arab Emirates had agreed to cooperate on defence, after Iran targeted countries in the area in retaliation for US-Israeli strikes.

An Israeli strike killed three journalists Saturday in south Lebanon, including a well-known reporter for Hezbollah's Al Manar network, with Lebanese authorities denouncing the attack as a "war crime".

The Israeli military confirmed killing Al Manar correspondent Ali Shoeib, accusing him of having "operated within the Hezbollah terrorist organisation under the guise of a journalist".

CAIRO, March 28 (Reuters) - Yemen's Iran-aligned Houthis confirmed on Saturday that they had launched an attack on Israel for the first time during the current Israeli-U.S. war against Iran, marking their entry to the conflict and raising the prospects of a broader regional confrontation.

Israel earlier said it was working to intercept a missile from Yemen.

By Matt Spetalnick, Nandita Bose and Humeyra Pamuk

WASHINGTON, March 28 (Reuters) - With global energy prices up and his job approval ratings down, Donald Trump faces starkchoices after a month of war against Iran: cut a potentially flawed deal and get out, or escalate militarily and risk a prolonged conflict that could consume his presidency.