US Secretary of State John Kerry made a brief, unannounced trip to Tunisia Tuesday to back the transition to democracy in the North African country that spawned the Arab Spring. His visit came amid troubled relations between the United States and longtime ally Egypt over the military overthrow of the Islamist government elected there in the aftermath of the 2011 uprisings that shook the Arab world. Tunisia's agreement earlier this year on a consensus government and a new constitution three years after the ouster of veteran dictator Zine El Abidine Ben Ali has been hailed as a model by Western governments uncomfortable about events in Egypt. Kerry met President Moncef Marzouki and caretaker Prime Minister Mehdi Jomaa, who formed a cabinet of independents in January after a months-long political crisis ignited by the assassination of two secular politicians. "We are very impressed by the steps that you have been taking, by the rational, thoughtful approach to the transition," Kerry told Marzouki. He congratulated Tunisia on its adoption last month of a new constitution that has been widely hailed as the most progressive in the region, calling it a "big step," and said he looked forward to elections planned for later this year. Before boarding the plane for France, his next stop, Kerry said the visit was intended to show Tunisians "that there are many, many countries and many people in the world who admire what people have been engaged in here." The top US diplomat often refers in his speeches to the Tunisian fruit vendor who set himself alight in protest at his country's lack of democracy. The shocking self-immolation sparked the January 2011 revolution that toppled Ben Ali and ignited the Arab Spring uprisings across the region. "What is unique, or at least striking in particular about Tunisia, is the willingness of opposing sides to reach out and show some inclusiveness and cooperation," a senior US official said, asking not to be named. - Progress despite violence - Tunisia's new leaders have grappled with a surge in Islamist unrest, which saw the murder of two opposition politicians, Chokri Belaid and leftist MP Mohamed Brahmi. That sparked a crisis between the governing Ennahda party, a moderate Islamist movement, and its secular opponents, from which the country is only now emerging with the adoption of the new constitution. Ennahda, which won Tunisia's first free elections in October 2011, stepped down in January under a hard-won agreement to end the crisis. That allowed Jomaa to form a cabinet tasked with leading the country to fresh elections. Despite the political progress, Islamist violence remains a threat, and the new leaders must also deal with persistent social unrest. More than 1,000 protesters gathered Monday in the town of Jendouba to condemn the weekend killings of four people by suspected jihadists. Kerry hailed the Tunisian security forces' success in arresting militants and breaking up Islamist cells in recent weeks, in operations he described as "well planned and executed." State Department officials have also said Washington wants to work with the authorities to bring to justice those behind a 2012 attack on its embassy and the American school in Tunis, after suspended jail terms were given to 20 suspects last year. "In our view there's more that could be done both in terms of arrests and prosecutions", a senior State Department official said. Washington has given some $400 million (292 million euros) in assistance to Tunis since 2011. Kerry was also to upgrade ties during his visit, announcing that they would launch a strategic dialogue, a high-level forum for regular talks. Washington's relations with Tunis contrast with those with Cairo, where army chief Field Marshal Abdel Fattah al-Sisi tilted squarely towards Moscow in a visit last week. Asked by journalists what lessons Egypt could learn from Tunisia, Kerry said he was "not going to advise General Sisi" at a press conference, but would talk to the Egyptian authorities personally in the coming days or weeks as part of a "continuing dialogue." Kerry left Tunis for Paris for a meeting Wednesday with Palestinian president Mahmud Abbas as the US seeks to hammer out an agreed framework to guide negotiations with Israel towards a peace treaty.