Attackers threw a grenade into the compound of truce monitors in Sri Lanka's restive east early on Saturday, damaging vehicles and a building but causing no injuries, officials said, as fears of a return to war grow, Reuters reported. The first direct attack against the monitors since a 2002 ceasefire halted a two-decade civil war came just hours after the Sri Lanka Monitoring Mission (SLMM) reprimanded both Liberation Tigers of Tamil Eelam rebels and the government over a spike in violence. "A hand grenade was lobbed into our compound in Batticaloa and exploded," said SLMM spokeswoman Helen Olafsdottir. "We don't know who was behind it. It is the first time one of our offices has been directly attacked." Some 60 unarmed monitors, all from Nordic countries, have been there since 2002. On Friday, they questioned whether there was still a ceasefire to monitor after more than 100 people were killed in December in attacks that have continued into January. Fears of a return to a war that killed more than 64,000 people before the truce are growing in tandem with deadly attacks by suspected rebels on the military and reported abuses by the armed forces against civilians. Suspected Tigers killed nine sailors in an ambush on a main supply route in Sri Lanka's north on Thursday. It came after similar ambushes killed 39 military personnel in December. Analysts are sceptical of rebel denials of involvement in the attacks, but say evidence suggests elements in the military are hitting back either directly or by helping renegade rebels target the Tigers, despite their denials. Diplomats and defence experts say both sides are engaged in an undeclared war that has hammered the stock market and could spiral into an all-out conflict that would choke a $20 billion economy dependent on textile and tea exports and tourism. "Killings and serious attacks continue and the situation is getting worse," the SLMM warned on Friday in a statement entitled "SLMM questions whether there is still a ceasefire in Sri Lanka". The Sri Lankan government has repeatedly said it will not be provoked into resuming war, but new President Mahinda Rajapakse is having to juggle the demands of hardline allies who hate the Tigers and an increasingly frustrated military. The Tigers have threatened to resume their armed struggle this year unless the government gives them a separate Tamil homeland and wide political powers in the north and east, where they already run a de facto state. The rebels say they want lasting peace, but they also say they are ready to use suicide bombers as in the past if war resumes.