US Secretary of State John Kerry arrived in the Middle East on Sunday for talks on the Iraq crisis, as Sunni militants made new gains in an offensive that has alarmed the world.
As Kerry landed in Cairo on a trip that will also take him to Amman, Iraqi government forces, fighting back against the insurgents after initially evaporating before their onslaught, launched air strikes on Tikrit, killing at least seven people, witnesses said.
The bombing of Tikrit, one of several cities that have fallen out of government control since the militants launched their offensive on June 9, came a day after Shiite fighters paraded in Baghdad in a dramatic show of force aimed at their Sunni opponents.
Washington's new diplomatic bid is aimed at uniting Iraq's fractious leaders and repelling insurgents whose lightning offensive has displaced hundreds of thousands, spooked the international community and put Prime Minister Nuri al-Maliki under growing pressure.
Kerry arrived on Sunday in Cairo, where he was due to meet President Abdel Fattah al-Sisi to press the former army chief, who ousted Egypt's first democratically elected president, to install greater political freedoms and discuss security challenges.
He was due later in Amman for talks with Jordan's Foreign Minister Nasser Judeh before carrying on to Brussels and Paris.
State Department spokeswoman Jen Psaki said Kerry would "consult with partners and allies on how we can support security, stability, and the formation of an inclusive government in Iraq".
While Kerry is also expected to travel to Iraq for his second visit since taking over as secretary of state in early 2013, it was not known when he would do so.
Washington had initially favoured Maliki when he first became prime minister in 2006 as he was seen to be cracking down on Shiite militias while reaching out to Sunni leaders.
But in recent months, he has made increasingly sectarian moves, triggering calls from US leaders to be the man for all Iraqi people -- including Sunnis, Kurds and Christians.
While US leaders have stopped short of calling for Maliki to step down -- arguing that it is up to the Iraqis to choose their own leaders -- they have left little doubt that they feel the Shiite premier has squandered the opportunity to rebuild his country since American troops withdrew in 2011.
"We gave Iraq the chance to have an inclusive democracy. To work across sectarian lines, to provide a better future for their children," President Barack Obama told CNN on Friday.
"Unfortunately, what we've seen is a breakdown of trust."
Obama has unveiled a plan to send 300 military advisers back to Iraq, but he made it clear that without political changes, the United States would not invest lives and resources in the country US forces invaded in 2003.
In a sign the broad alliance of jihadists and anti-government elements behind the assault may be fracturing, internecine clashes killed 17 fighters in northern Iraq.
But officials said insurgents led by the Islamic State of Iraq and the Levant (ISIL) group seized one of three official border crossings with Syria on Saturday.
The takeover came a day after 34 members of the security forces were killed in the border town, giving the fighters greater cross-border mobility into conflict-hit Syria.
The seizure of Al-Qaim leaves just one of three official border crossings with Syria in the hands of the central government. The third is controlled by Kurdish forces.
Anti-government fighters already hold parts of the western province of Anbar, which abuts the Syrian border, after taking all of one city and parts of another earlier in the year.
ISIL aims to create an Islamic state that will incorporate both Iraq and Syria, where the group has become a major force in the rebellion against President Bashar al-Assad.
The Sunni insurgents driving the offensive are made up of a broad alliance of other groups, such as loyalists of executed dictator Saddam Hussein.
Analysts say it is unclear if the alliance can survive given its disparate ideologies.
In Baghdad, thousands of armed fighters loyal to powerful Shiite cleric Moqtada al-Sadr paraded in the Sadr City district, vowing to fight the offensive which began on June 9.
Rank upon rank of fighters, wearing mostly camouflage but with some in black, carried Kalashnikov assault rifles, shotguns, sniper rifles, light machineguns and rocket launchers.
UN aid agencies said they were rushing supplies to Iraq to help more than one million people displaced by the latest violence and unrest earlier this year.