By Daphne Psaledakis

WASHINGTON, Feb 4 (Reuters) - U.S. President Donald Trump has attacked key pillars of his country's democracy, Human Rights Watch warned on Wednesday in its annual global report, citing the Republican president's immigration crackdown, threats to voting rights and other policies.

By Bo Erickson

WASHINGTON, Feb 4 (Reuters) - U.S. first lady Melania Trump said on Wednesday she remains in contact with Russian President Vladimir Putin's team in an effort to secure the return of more Ukrainian children from Russia.

"I'm working on it, and we are in the process," she told reporters at the White House. "I hope we have success very soon."

She did not share details about talks between her representatives and Putin's team.

WASHINGTON, Feb 4 (Reuters) - U.S. talks with Iran will take place on Friday in Oman, a U.S. official confirmed on Wednesday, after Iranian Foreign Minister Abbas Araqchi said that nuclear talks with the U.S. are set to be held in the Omani capital Muscat at around 10 a.m. on Friday.

(Reporting by Humeyra Pamuk; Writing by Daphne Psaledakis; Editing by Doina Chiacu)

Iran and the United States said Wednesday they were going ahead with nuclear talks in Oman later this week, even as President Donald Trump piled pressure on Tehran's supreme leader by saying he should be "very worried."

Doubts had swirled about the fate of the negotiations after a report earlier Wednesday that the talks between the bitter foes were falling apart due to disagreements about the format and the venue.

By Aislinn Laing

MADRID, Feb 4 (Reuters) - Telegram founder Pavel Durov on Wednesday joined Elon Musk in publicly criticising plans by Spanish Prime Minister Pedro Sanchez to ban social media access for under 16s and to prosecute executives for hate speech on their platforms.

Durov said in a message to Telegram users that the proposal to block children would force social media platforms to gather the data of all users and measures to curb hate speech would prompt platforms to strip content to avoid prosecution.

TUNIS, Feb 4 (Reuters) - Tunisian police arrested lawmaker Ahmed Saidani on Wednesday, two of his colleagues said, in what appeared to be part of an escalating crackdown on critics of President Kais Saied.

Saidani has recently become known for his fierce criticism of Saied. On Tuesday, he mocked the president in a Facebook post, describing him as the “supreme commander of sewage and rainwater drainage,” blasting what he said was the absence of any achievements by Saied.

(Reporting by Tarek Amara; editing by Mark Heinrich)

BERLIN, Feb 4 (Reuters) - German Chancellor Friedrich Merz began a tour of Saudi Arabia, Qatar and the United Arab Emirates on Wednesday aiming to forge energy and arms partnerships as Europe's biggest and richest economy sought to reduce dependence on the U.S. and China.

"We need such partnerships more than ever at a time when politics is increasingly being determined by major powers," Merz said at the start of his three-day trip, adding the aim of such alliances was to preserve freedom, security and prosperity.

As Israel begins to allow a trickle of Palestinians through the Rafah border crossing, Gazans stranded in Egypt are torn between staying in exile without formal status or returning to a land in ruins.

"Return to Gaza for what? To live in a tent?" demanded Mohamed, a 78-year-old poet from Beit Lahia in northern Gaza.

"We have not turned our backs on Gaza, we will return. But right now, we cannot go back under these conditions," he told AFP, asking to be identified only by his first name.

Seif al-Islam, the son of Libya's slain longtime ruler Muammar Gaddafi and once seen by some as his likely heir, has been killed.

Targeted by a warrant from the International Criminal Court for alleged crimes against humanity, and still a player in Libya's turbulent political scene, the 53-year-old was no stranger to violence.

But his sudden assassination has raised many questions:

- Who is behind it? -

Very little has emerged about the identity or motives of the assailants.

By Angeliki Koutantou and Yannis Souliotis

ATHENS, Feb 4 (Reuters) - Fifteen migrants died after their boat collided with a Greek coast guard vessel, capsized and sank off the island of Chios in the Aegean Sea late on Tuesday, the coast guard said, in one of the deadliest migrant shipwrecks in Greece in years.

The incident occurred after a migrant boat sailing towards Chios with its navigation lights switched off ignored signals from a coast guard patrol vessel and changed course, the coast guard said in a statement.