Turkey has sent groundtroops into Iraqi Kurdistan to fight PKK rebels, who have bases in the region.

"Turkish security forces crossed the Iraqi border as part of the hot pursuit of PKK terrorists who were involved in the most recent attacks," a government source told AFP news agency.

"This is a short-term measure intended to prevent the terrorists' escape."

Air strikes on PKK bases were also launched on Tuesday, in further escalation of the violence.

A UN backed tribunal began in Cambodia on Monday trying the two surviving leaders of Khmer Rouge regime of the crime of genocide.

Last year both Khieu Samphan and Nuon Chea were found guilty of war crimes and crimes against humanity, but Monday’s trial will see them face charges of genocide. The trial will examine crimes carried out against ethnic Cham Muslims and ethnic Vietnamese during the Khmer Rouge’s 1975-79 rule.

The prosecution stated that 90 percent of the 200,000 ethnic Vietnamese population in the country were forcibly deported by the regime, and the remaining 20,000 were killed in a process that "involved mass killings of Vietnamese civilians who were sought out solely on the basis of their ethnicity."

The prosecution also alleged the Khmer Rouge "succeeded in physically destroying a significant portion of the Cham population, solely because of their ethnic and religious background."

This effort included removing Cham women and children from the group and placing them in Khmer communities, forcing Cham to marry outside their ethnic group, and banning all cultural aspects traditionally identified with that group," it said, adding the campaign "culminated in 1977 and 1978 with organized mass executions of entire Cham communities conducted by [Khmer Rouge] cadres in multiple [areas of Cambodia]".

Two British men were killed after being targeted in a drone strike, carried out by the Royal Air Force.

Reyaad Khan, 21, from Cardiff and Ruhul Amin from Aberdeen were both members of the Islamic State militant group and were hit on August 21 in an “act of self-defence” according to British Prime Minister David Cameron.

Mr Cameron accused Mr Khan of plotting “barbaric” attacks and said the drone strike was lawful and necessary.

The prime minister added the targeting of the men was approved by the attorney general.

In his statement to the Commons, Mr Cameron said: "My first duty as prime minister is to keep the British people safe.

"There was a terrorist directing murder on our streets and no other means to stop him.

"This government does not for one moment take these decisions lightly.

"But I am not prepared to stand here in the aftermath of a terrorist attack on our streets and have to explain to the House why I did not take the chance to prevent it when I could have done."

However Labour leader Harriet Harman questioned the legality of the attack and called for “independent scrutiny”.

Chad's former dictator Hissene Habre was forcibly brought into court and held down by masked security officers at the resumption of his trial in Senegal for war crimes and crimes against humanity.

The 72 year old is accused of being responsible for the deaths of 40,000 Chadians during his 1982-1990 rule. Mr Habre has refused to recognise the African Union backed court and repeatedly disrupted proceedings. He shouted abuse at court officials throughout Monday’s proceedings, yelling "Shut up! Shut up!" at the court clerk as his indictment was read.

Reed Brody, a counsel at Human Rights Watch said,

The leader of the Democratic Unionist Party (DUP), Peter Robinson, says there will be no meetings of the Northern Ireland Executive unless in “exceptional circumstances”, as the crisis Stormont was plunged into after the killing of a former IRA member, escalates.

Mr Robinson, who is also First Minister of the assembly, said the DUP's ministers would focus on talks to try to resolve the crisis that are due to begin on Tuesday.

Police have said they believe members of the Irish Republican Army were involved in the murder of Kevin McGuigan Snr, however added there was no evidence at this stage to suggest the shooting was sanctioned by the organisation.

Republican party Sinn Féin rejected the police’s accusation and said the IRA had "gone" and was not "coming back".

A Dutch journalist who was covering clashes between Kurds and Turkish police was was arrested in the country's southeast.

Frederike Geerdink was previously arrested in January on charges of aiding Kurdish militants, but was acquitted and released.

In an interview after her release, the journalist explained why she had decided to remain in Turkey.

"I have chosen this life and if I want it to be different I can go back to my own country," she told The Independent.

Several Turkish soldiers were killed in an attack by Kurdish militants in Hakkari in the southeast of the country.

The PKK claimed responsibility for the attack and said 15 soldiers died.

Turkish media said bombs were detonated as two military vehicles were passing in the village of Daglica.

President Recep Tayyip Erdogan promised "a very particular and decisive" response, while speaking on  Turkish TV.