Turkish President Recep Tayyip Erdogan Tuesday filed a lawsuit against the main opposition chief for claiming his vast palace had gold-plated toilet seats, in an increasingly acrimonious row over the alleged lavatory luxuries ahead of June 7 elections.

Erdogan's lawyer Muammer Cemaloglu is seeking 100,000 Turkish Liras ($37,300) in compensation for slander from Kemal Kilicdaroglu, leader of the Republican People's Party (CHP), the state-run Anatolia news agency reported.

Turkish President Recep Tayyip Erdogan on Monday invited the opposition to inspect his gigantic presidential palace for gold-plated toilet seats, vowing to resign if they could prove their allegations of his bathroom bling.

Erdogan's 1,150-room palace, which was built at a cost of around 490 million euros ($615 million), has been condemned by critics as an absurd extravagance and held up as proof he is slipping further into authoritarianism.

Turkish police on Sunday tightened security around Istanbul's Taksim square, on the second anniversary of the mass anti-government protests that rocked the square in 2013.

Police blocked major roads leading to the square and the adjoining Gezi Park, and public transport links in the area were suspended, an AFP photographer said.

The Islamic State jihadist group launched an assault on the largely Kurdish city of Hasakeh in northeast Syria on Saturday, the Syrian Observatory for Human Rights said. 

The attack came a day after Kurdish militia executed 20 civilians accused of supporting the extremists, the monitoring group said.

Turkish authorities announced Friday they had taken control of the country's 10th largest lender, Bank Aysa, which is linked to an ally-turned-foe of President Recep Tayyip Erdogan, U.S.-based cleric Fethullah Gulen.

In a statement, the Banking Regulation and Supervision Agency said it had handed over the reins of the bank to the state-run Savings Deposit Insurance Fund (TMSF) eight days before legislative elections on June 7.

The Syrian government has abandoned Idlib to concentrate on regions deemed vital for its survival, a security source and monitor said Friday, allowing al-Qaida to seize the province's last regime-held city.

Rebels now control the vast majority of Idlib province after al-Nusra Front -- al-Qaida's Syrian affiliate -- and its allies overran Ariha and surrounding villages on Thursday.

Images and video footage allegedly showing trucks belonging to Turkey's state intelligence service carrying weapons to rebels in Syria were published Friday in a Turkish daily.

The Turkish government has vehemently denied claims that it is arming rebels fighting in Syria and accused dozens of prosecutors, soldiers and security officers involved in searching the trucks of attempting to bring it down by suggesting it is doing so. 

The Greek and Turkish Cypriot leaders agreed Thursday to open more crossing points and link the mobile phone and electricity networks to help restore trust between their estranged communities on divided Cyprus.

Practical steps such as integrating the electricity grid and linking the mobile phone networks are seen as non-sensitive issues that would bring Cypriots closer under a renewed climate of reconciliation.

A U.S. man pleaded guilty Wednesday to providing material support to Islamic State militants after attempting to travel overseas to join the group, the Department of Justice said.

Leon Nathan Davis was arrested in the Atlanta airport in the southern state of Georgia last October as he attempted to fly to Turkey.

The campaign for Turkey's June 7 legislative elections has been rich in political point-scoring while ignoring one of the biggest challenges the country faces in the years ahead -- the future of the almost two million refugees from the civil war in Syria.

Turkey is hosting 1.8 million Syrian refugees, more than any other country, and they have already become significant minorities in several cities, causing social tensions.