London - Two brothers on Tuesday pleaded guilty in a British court to conspiring to attend a terror training camp in Syria.
Mohommod Nawaz, 30, and Hamza Nawaz, 24, were arrested in September as they entered the port of Dover on the southeast English coast.
Officers who searched their car allegedly found five rounds of ammunition for an AK-type gun, a balaclava, some "heavy-duty clothing", six mobile phones and a SIM card inside a Qur'an.
The men, from Stratford in east London, allegedly drove to France, then flew to Turkey before travelling over the border into Syria.
At the Old Bailey central criminal court, the brothers pleaded guilty to conspiring to attend a place used for terrorist training between 1 January 2012 and 16 September 2013.
Mohommod Nawaz also pleaded guilty to having ammunition without a firearms certificate, while the same charge against his brother was ordered to remain on file.
They will be sentenced on 9 June.
The prosecution decided not to proceed with charges against a brother and sister living at the same address as the Nawaz brothers.
Following the brief court hearing, police urged worried families to contact officers if they thought relatives were planning to go to Syria.
"Travelling abroad to engage in terrorist-related activity is a serious offence and we will continue to prosecute, where appropriate, anyone engaged in this type of activity," said deputy assistant commissioner Helen Ball, the senior national coordinator for counter-terrorism.
"Our concerns include the actions of people who have attended terrorist training camps or who have fought in war zones, as well as the possibility that they return to the UK radicalised."
Police said last month that the numbers of Britons travelling to Syria were in the low to mid-hundreds, although other estimates put the figure at 400, with 20 Britons having been killed.
On 20 May a 31-year-old man became the first person to be convicted in Britain of terror offences related to the conflict.
Mashudur Choudhury, from Portsmouth on the southern English coast, travelled to Syria in October with the intention of attending a terrorist training camp, his trial heard.
He will be sentenced on 13 June.