Carter said his aim was to "form my own on-the-ground assessment of the campaign," referring to Iraq's efforts to reclaim the key city of Ramadi, which was taken by "Islamic State" ("IS") in May.

It was Carter's first visit to Iraq since he took office in February. He was not expected to announce a major change in US policy, nor an increase in troop numbers.

His visit came after the Iraqi government announced a counteroffensive to retake Ramadi last month, the capital of Anbar province. The actual assault on the city has not yet begun, but a Pentagon spokesman said it could start within a few weeks.

The campaign is a crucial test for Prime Minister Haider al-Abadi and his government's attempts to overcome IS in cooperation with a US-led coalition targeting IS from the air.

US President Barack Obama has ruled out deploying ground forces in Iraq, insisting that the only solution for Iraq is to eventually fight for itself. US troops officially withdrew from Iraq at the end of 2011.

Sectarian strife

But Iraq's campaign is being hampered by sectarian strife. Despite US forces still providing on-the-ground training, there are question marks as to whether the Shiite-led government in Baghdad and its mainly Shiite forces can overcome the sectarian divide that has helped fuel the Islamic State's expansion in Anbar.

Carter is therefore also meeting Sunni leaders, which the US believes have to be part of the fight against IS.

Carter's visit comes at a sensitive time in US-Iraq relations. After Iraqi troops abandoned Ramadi in early May, handing IS its biggest battlefield victory of 2015, Carter caused a stir in Iraqwhen he said its army "just showed no will to fight."

He pointed to the fact that Iraqi forces were not outnumbered in Ramadi, yet they had abandoned their weapons and equipment, including dozens of American-supplied weapons.

Meanwhile on Thursday, the Reuters news agency reported that IS claimed responsibility for a link:18602694:suicide car bombing# in a mainly Shiite Muslim district of Baghdad that killed at least 20 people the day before. IS is an extremist Sunni group.

ng/kms (Reuters, AP)