A Gazan shopkeeper is selling souvenir mugs to mark the U.S.-hosted Middle East peace conference with instructions to customers to smash them if the diplomacy drivein pieces. The mugs are marked with a dove and olive branch -- symbols of peace -- and a message in English: "Note: Please keep this souvenir, but in case of the conference's failure; you are only asked to break the mug". Tareq Abu Dayya, who also sells flags and T-shirts from his souvenier shop in Hamas-run Gaza, said the mugs were a sign of hope Tuesday's (November 27) conference could yield talks about Palestinian statehood but also reflected low expectations for success. Dayya cautioned he would not refund customers if talks collapse without a deal. Palestinian President Mahmoud Abbas arrived in Washington on Sunday (November 25) ahead of the conference in nearby Annapolis, which the U.S. hopes will relaunch talks about creating a Palestinian state. Islamist group Hamas, which routed Abbas's forces in Gaza in June, has not been invited. In the isolated Gaza Strip, Hamas and other militant groups condemned the conference, saying the summit attended by some 40 countries, including Arab league states, contradicts the rules of Islam. "All the Arab and Palestinian representatives in Annapolis are all unreliable witnesses of the siege and slaughter," said a spokesman of the Islamic Jihad militant group. Hamas also condemned the decision by Arab powers to endorse the conference, saying it would favour the Jewish state's policies rather than Palestinian demands. Hamas, which refuses to recognise Israel and broke with Abbas after seizing control of the Gaza Strip in a June civil war, is excluded from the conference. Arab League ministers agreed on Friday (November 23) to attend the conference in the hope of promoting the creation of a Palestinian state and pushing for Israel to return the occupied Golan Heights to Syria as part of a regional peace process. Saudi Arabia, long a Hamas patron, has said it will come to Annapolis despite having no formal ties with Israel. The Arab League has offered Israel recognition if it quits lands captured in a 1967 Middle East war and agrees to solving the Palestinian refugee problem. Israel has balked at discussing "core issues" like refugees and borders at this stage. Meanwhile, in the refugee camp of al-Mallacha, residents voiced worry over their livelihood. Some hoped the peace talks would address the issue of refugees and allow hundreds of thousands of Palestinians to fullfil their "right of return". Others seemed indifferent, arguing the conference would not help easing Palestinian hardships. The Annapolis talks, set for Tuesday, take place amid a growing surge of violence across the region. Israeli forces, backed by armoured vehicles and bulldozers, operated in northern Gaza near the Erez border crossing. The bulldozers demolished several houses, witnesses said. Palestinians later reported that three militants were wounded during clashes with Israeli troops in the area. Also on Sunday hundreds of mourners marched in a funeral procession for two militants killed by Israeli troops according to local medical workers. An Israeli army spokeswoman said troops had spotted two men kitted out in magazine belts, one of whom was armed. The soldiers opened fire at the two men and killed then when they came close to the troops. Local residents said the two men were killed while the forces operated close to the Mghazi refugee camp in the central part of the Gaza Strip. The two were buried in the southern Gaza town of Khan Younis. A spokesman for militants said one of the men was a member of the Islamic Jihad group and the other was aligned with the Popular Resistance Committees. Israel has stepped up air strikes and military incursions since Islamist Hamas seized control of Gaza in June. Gunmen often lay ambush for roving Israeli commandos in frontier areas.