BELGRADE, Dec 23 (Reuters) - Montenegro on Tuesday revoked its decision to insist on visas for Turkish citizens and reintroduced a visa-free regime but for a shortened duration, citing improved cooperation with Turkish authorities.

Following violence triggered by the stabbing of a Montenegrin man in the capital Podgorica by a group of Turks, Montenegro in October suspended a regime that had allowed visa-free stays of up to 90 days for Turkish nationals.

London police on Tuesday arrested Swedish activist Greta Thunberg at a demonstration in support of pro-Palestinian hunger strikers, Palestinian campaign groups said.

Thunberg's arrest makes her the highest profile person to be detained by police since the government banned the Palestine Action group under anti-terror laws.

Prisoners for Palestine, which organised the protest, said in a statement that Thunberg was arrested under the UK Terrorism Act.

Thunberg, 22, was holding a sign reading: "I support the Palestine Action prisoners. I oppose genocide."

By Sam Tobin and Andy Bruce

LONDON, Dec 23 (Reuters) - Two men were found guilty on Tuesday of plotting to kill hundreds in an Islamic State-inspired gun rampage against the Jewish community in England, a planned attack investigators say demonstrates the resurgent risk posed by the militant group.

CAIRO, Dec 23 (Reuters) - Two vessels from CMA CGM, the world's third-largest container shipping line, have travelled through the Suez Canal, the authority that runs the waterway said on Tuesday, in a sign the disruptions linked to the Gaza war could be easing.

While the Suez Canal provides the fastest link between Asia and Europe, since November 2023, shipping companies have had to take much longer routes because Yemen's Iran-aligned Houthi militants attacked commercial vessels, saying they were acting in solidarity with Palestinians during warfare in Gaza.

Dec 23 (Reuters) - The Trump administration is not satisfied with the Rwanda-backed M23's withdrawal from a strategic town in eastern Congo, a senior U.S. official told Reuters, as residents reported persistent clashes nearby on Tuesday.

M23 seized the town of Uvira, near the border with Burundi, on December 10, days after Congolese President Felix Tshisekedi and Rwandan leader Paul Kagame met President Donald Trump in Washington and reaffirmed a U.S.-brokered peace deal.

MOSCOW, Dec 23 (Reuters) - Russian Foreign Minister Sergei Lavrov will hold talks with his Syrian counterpart Asaad Al-Shaibani in Moscow on Tuesday, the TASS state news agency reported, citing ministry spokeswoman Maria Zakharova.

(Reporting by Reuters; Writing by Gleb Stolyarov; Editing by Andrew Osborn)

JERUSALEM, Dec 23 (Reuters) - Israeli Defence Minister Israel Katz said on Tuesday that the military would never fully withdraw from the Gaza Strip for security reasons and that a civilian-military army unit would be established in the Palestinian enclave.

According to a U.S.-backed peace plan signed by both Israel and Hamas in October, the Israeli military will gradually withdraw completely from the coastal enclave and Israel will not re-establish civilian settlements in the coastal territory.

LONDON, Dec 23 (Reuters) - British police arrested Swedish activist Greta Thunberg in London on Tuesday at a pro-Palestinian protest, UK-based campaign group Defend Our Juries said.

Thunberg was arrested under the Terrorism Act for holding a sign that said she supported prisoners linked to Palestine Action, an organisation which the British government has proscribed as a terrorist group, Defend Our Juries said.

A City of London spokesperson said two people had been arrested for throwing red paint on a building.

By Ali Kucukgocmen

KONYA, Turkey, Dec 23 (Reuters) - Hundreds of sinkholes have emerged in Turkey's central agricultural region due to dwindling rainfall and receding groundwaters, causing concern among farmers and environmental experts who see it as a worrying sign of climate change.

Gaping sinkholes pockmark farmland producing maize, wheat and sugar beet in Karapinar in Konya province, with more than 10 packed into a field in places. In mountainous areas, vast, ancient sinkholes previously filled with water have now mostly dried up.

Dec 23 (Reuters) - Australian Prime Minister Anthony Albanese said on Tuesday he called Israeli President Isaac Herzog and invited him to visit Australia, expressing his shock and dismay over the attack at the Jewish community Chanukah event on Bondi Beach last week.

Herzog said he would accept the invitation and mentioned that the President of the Zionist Federation of Australia also sent him an official invitation expressing their wish for him to visit, and he intends to do so, Albanese said in a post on X.